Laveen, Arizona (CNN) -- Daniel Adkins knew his son would never leave Lady. So when animal control officers showed up at the door with Daniel Jr.'s yellow lab in tow, "I felt like he was calling out to me for help."

Something was definitely wrong.

Adkins and his wife, Antonia, had searched the neighborhood just hours earlier, tracing their missing son's footsteps down two miles of dusty road to a cluster of strip malls. But they didn't make it as far as the Taco Bell. If they had, they would have come across the flashing police lights and the body of Daniel Jr., lying on the asphalt by the drive-thru window, with Lady by his side.

The next morning brought two police detectives bearing news that Daniel Jr., who was 29 but had the mental capacity of a 13-year-old, had been shot and killed. The shooter said he acted in self-defense. He has not been charged.

Adkins' death on April 3 marks the most recent chapter in America's debate over the right to use lethal force. The controversy has ricocheted from coast to coast ever since unarmed teenager Trayvon Martin was shot to death in Sanford, Florida, on February 26.

The Martin case renewed scrutiny of Florida's 2005 "Stand Your Ground" law after Sanford police initially declined to arrest Martin's shooter, a neighborhood watch volunteer. George Zimmerman has now been charged with second-degree murder but likely will invoke self-defense.

In Arizona, where the Adkins family lives, a similar law was enacted in 2006, tacked on to another gun bill after a gun rights lobbyist promoted it for 20 seconds in front of the Senate Judiciary Committee. Called "Make my Day," it says people have no duty to retreat before using deadly force to protect themselves anywhere they have the legal right to be.

Arizona and Florida are not alone in enacting these laws. Thirty-one other states also have laws that expand the use of deadly force beyond the home. People who kill armed intruders in their homes already were protected under the Castle Doctrine, the legal notion that your home is your castle and you have the right to use lethal force to defend it.

Interactive: Does your state have expanded self-defense laws?

CNN reviewed four deadly force cases, each with a unique set of circumstances that tested the boundaries of Stand Your Ground laws. Each also raises questions about where the line is drawn between legitimate fear and vigilantism.

Is the use of deadly force justified when the attacker has no weapon and doesn't touch the person who feels threatened? If an intruder has been subdued, is shooting him or her justified? Can a person chase someone down and then claim self-defense? Are Stand Your Ground laws necessary or were existing laws enough?

Guns always have been a part of American life. The right to bear arms was addressed in the Second Amendment of the U.S. Constitution. But the law continues to evolve to this day, said Laurie Levenson, a professor at Loyola Law School in Los Angeles, California.

"When you arm people on the streets, the opportunities for tragic shootings like the one in the Martin case increase," Levenson said. "Having a broader law lends itself to situations where people shoot instead of pursuing non-lethal alternatives for self-defense."

The current debate over Stand Your Ground is healthy, Levenson added.

"It is good that people are starting to rethink what we have done," she said. "Given the number of guns on the street, it is important that people not use self-defense laws as an excuse for unjustifiable shootings."

A study commissioned by the National District Attorneys Association in 2007 tied the trend toward expanding self-defense laws to citizens' lack of confidence in the justice system in the wake of the September 11 terrorist attacks and Hurricane Katrina. People did not feel safe, and they did not trust their government to protect them.

But the expanded self-defense laws worry police and prosecutors, according to the study. Chief among their concerns: Could the laws lead to what the study called "an increasingly armed and trigger-happy citizenry?"

Meet the architect of Florida's Stand Your Ground law

Shot 'straight in the heart'

The confrontation that would catapult two more families into the middle of the lethal force debate began as the sun dipped below the horizon in Laveen, Arizona, a suburb southwest of Phoenix.

It was April 3 -- 37 days after Martin's death in Florida. Daniel Adkins Jr. walked past Taco Bell's drive-thru just as a 22-year-old man pulled around in his SUV to pick up his order. Sitting in the passenger seat was his pregnant fiancée.

CNN is withholding the shooter's name because he has not been charged with a crime. A police report describes how the deadly confrontation unfolded.

The driver slammed on the brakes, just missing Adkins. The two men exchanged words.

The shooter told police that Adkins "air swung" his hands in the direction of the SUV, but acknowledged he never hit him or his vehicle. Still, he said, he was afraid of what Adkins might do with the weapon he believed he was carrying. Although a weapon was never found, the shooter described it as a 3-foot metal pipe or bat.

When Adkins lifted his hands in the air again, the driver drew his Smith and Wesson .40-caliber handgun from his sweatpants. He pointed the barrel at Adkins from inside his car and racked the slide of the gun, putting a bullet in the chamber. Then he pulled the trigger.

Struck in the chest, Adkins fell to the ground, face first, clutching Lady's leash. The lab stayed at her master's side, even as the life drained out of him.

The shooter pulled around to the front of the Taco Bell as his fiancée called 911.

He told police he had no choice but to shoot. He said he couldn't drive away from Adkins because the dog was in the way and he "thought he had no other options," according to the police report.

While the shooter said he did not believe Adkins would have killed him and his fiancée had he not fired, he also said he feared Adkins was trying to hurt him.

Police turned over their findings to the district attorney's office. Prosecutors have sent it back for further investigation.

CNN was unable to locate the shooter but spoke with a man who identified himself as his father. The man didn't want to be named and stood behind the door of his home, warning that he had a gun in his hand. He defended his son's right to use deadly force.

He said witnesses at the scene told him that Adkins "went beserk" on his son, raising his hands and yelling: "What the hell, you almost hit me" and to "watch where the f*** you're going."

As the shooter's father recounted the events of that night, Adkins' family sat together in their living room a few blocks away, searching for answers. They believe their son was the victim of a trigger-happy young man.

Above the couch, Daniel Jr. seemed to look down at them from a photograph. They still can't believe that four weeks have passed and the man who killed him is free and in the same neighborhood where they live. They want to know: What else needs to be investigated?

Their thoughts turn to the funeral, and they begin to cry.

They bought Daniel Jr. a teddy bear for Easter but didn't get to give it to him. Instead, they placed it at a memorial for him at Taco Bell. Easter Sunday became a day to say goodbyes.

"We're at a funeral viewing my brother in a coffin while [the shooter] is at home with his family," said Marina Reyes, Daniel Jr.'s sister. "It's not fair to us. We need justice for Daniel. We need this guy behind bars because he does not deserve to be out."

The specter of Florida's Trayvon Martin case haunts both families.

The shooter's father worries that his son will be seen as another George Zimmerman."This is not like that case," the father said. "This guy was attacking my son."

Adkins' father worries that the politics swirling around the Martin case may give Arizona police and prosecutors cold feet about pursuing his son's shooter.

He believes in gun rights, but says people need to "be responsible and know when to use one."

"Why didn't he shoot my son in the leg? It would've stopped him. He hit him right straight in the heart. He shot to kill."

The loss of their son, and the circumstances in which he died, have tied the Adkins family to Trayvon Martin's. After Daniel Jr. was killed, they wrote Martin's parents a letter.

"Nobody knows the pain of losing a son in this way besides them," said Adkins' father. "His mother, she just wants justice for her son, just like we do. I'll go anywhere it takes, talk shows, make signs, whatever it takes."

"I'm not letting my son die in vain."

Reluctant symbol

James Workman never wanted to be the poster boy for the nation's first Stand Your Ground law. But an elderly hurricane victim made a compelling symbol.

Shortly after 2 a.m. on November 3, 2004, Workman shot and killed 35-year-old Rodney Cox, a FEMA worker from North Carolina who had come to his house near Pensacola, Florida, and asked for a drink of water.

Workman and his wife, Kathryn, were staying in an RV in the driveway of their home. Hurricane Ivan had made landfall seven weeks earlier, collapsing their front porch and peeling back the roof. The damaged house was unlivable.

It was a scary time on Florida's Perdido Key. People were camped out everywhere, and nerves were frayed. It felt like they were living in a war zone.

Just a week or two before, police subdued a man with a machete at the house next door. And a few days earlier, while they were away, someone in a camper parked in front of their house, used their hose and left the water running.

On a recent weekday, Kathryn Workman, now 62, stood with her husband in front of their tidy brick house with the sweeping view of Big Lagoon and the sugar sand dunes along the Gulf of Mexico. She stepped around her driveway, re-enacting events still vivid in her mind.

It was warm and windy that night and she couldn't sleep. As she reached to adjust a window, she spotted a stranger headed toward the front door of the house. She woke her husband, who grabbed his .38, and stepped outside.

The stranger mumbled and asked for a drink of water. Workman ordered him to "Get on out of here," and fired the warning shot into the grass. Instead, the man bolted toward the trailer where Kathryn was backed up against the kitchen sink, a phone in one hand and her own .38-caliber handgun in the other.

She screamed, telling the 911 dispatcher: "He's in the trailer. He's in the trailer with us. ... Please, oh please God ... He is in here."

There were sounds of a struggle. Seconds later, Kathryn Workman told the dispatcher her husband had shot the intruder.

"He dropped down after a point, and then he got back up," she told CNN, adding that she and her husband tried to edge him toward the RV door. "He died, well, I don't know if he was dead then, but he collapsed right in front of our TV."

When the police came, they had to escort the couple over the body. It was blocking the only way out.

How Rodney Cox, the man Workman shot and killed, came to be on the couple's front lawn -- and inside their trailer -- remains a mystery. But his sister, Terri Lavery, says he was not a drunken, drug-addled drifter up to no good. He was the father of two, married to his high school sweetheart, a successful building contractor who "was kind of preppie."

And on that night, he was a man looking for help.

A few hours before he was shot to death, Cox had called 911 himself, saying he was a victim of domestic violence. It was his first night in the Pensacola area, and he was staying in a camper about two miles from the Workman house.

But he kept giving the dispatcher the wrong address, explaining in frustration, "I'm not from around here."

The deputy who found Cox reported that the man appeared to be intoxicated, describing him as "very jumpy" and "unable to stand still." He said Cox had trouble completing his sentences and was difficult to understand. He did not make note of any injuries.

At some point during the evening, Cox had been hit over the head. The blow was hard enough to fracture his skull, an autopsy showed; his sister believes this may explain his erratic behavior.

Workman knew none of that at 2 a.m., of course. It was dark, his wife was screaming, a stranger was holding him in a bear hug, and there was no time to think it all through.

"We didn't have time to psychoanalyze him," Workman explained.

He added that he made his decision in a heartbeat and feels he was justified. After reviewing the case for nearly four months, a prosecutor agreed and decided not to file charges against Workman.

Lawmakers in Tallahassee seized on the Workman case as they considered the nation's first Stand Your Ground law. Rep. Dennis Baxley, co-sponsor of the law, said law-abiding people shouldn't have to wait months for prosecutors to rule a shooting in self-defense is justified.

"You have a 77-year-old gentleman and a perpetrator breaks into the RV to attack him," Baxley said. "It's months before he knows he's not going to be charged with a crime for simply defending his own life and his own property. That's not right. That's not how we do things here."

Florida already had a law on the books based on the Castle Doctrine -- the legal notion that your home is your castle and you have the right to use lethal force to defend it.

Stand Your Ground expanded the Castle Doctrine outside the home to any place a person had a legal right to be. It eliminated the need to take a step back before using lethal force on someone posing a threat. And, it offered the presumption that lethal force was justified.

Even though Workman's experience became the catalyst for the law, he was never asked to testify at the legislative hearings. He said he spoke to no one in Tallahassee. He learned about Florida's new law on the evening news.

"Nobody ever asked us," he said.

Workman, now 84, is reluctant to tell his story. "We don't want to be portrayed as gun-waving nut cases," his wife, Kathryn, explained.

Nobody can say how Cox fractured his skull, and police apparently never looked into it.

The Workmans told his sister they did not see Cox hit his head. When he fell after being shot, they said, he fell to his knees.

"I just want to know if someone seems disoriented and asks for a glass of water, why do you have to shoot him?" Lavery said. "My brother was injured. He was trying to get help. Instead he got shot, twice, and died at the age of 35."

She added, "I think everybody was on edge, and maybe a little trigger happy."

Self defense or 'execution?'

Jose Luis Gonzales loved spending weekends at his ranchette outside the border town of Laredo, Texas. But by the summer of 2007, he'd grown frustrated with the burglaries occurring at his house. So when four boys, ages 11 to 15, broke in around midnight one night in July, Gonzales greeted them with a shotgun.

What happened next depends on who is telling the story. But one thing is indisputable: At the end of the night, 13-year-old Francisco Anguiano was dead, shot in the back.

The landmark case over Texas homeowners' right to defend their property was all anyone in town could talk about. It raised questions about how far someone can go -- and what it means to defend yourself using deadly force.

Texas passed its Stand Your Ground law in 2007, extending the right to defend oneself not just at home, but also in the workplace or in a vehicle. Under the law, you can use deadly force if you reasonably believe it immediately necessary to protect yourself and prevent certain violent crimes, such as murder, aggravated kidnapping, sexual assault or robbery.

The boys entered Gonzales' home looking for snacks, said Uriel Druker, the Webb County district attorney at the time. They came from a neighborhood where several homes had little or no running water, he noted.

But Gonzales had no inkling about the boys' intentions, said his lawyer, Isidro Alaniz, who is now the district attorney in Webb County, where the shooting took place. He argued that Gonzalez had the right to use deadly force because the boys had broken into his home.

Gonzales confronted the boys and, holding a shotgun, asked them what they were doing in his home, attorneys said. He ordered the boys to get down on their knees.

He told one boy to "drop it," prosecutor Druker said. A bag of Cheetos fell to the floor. The boys testified at trial that Gonzales then smacked them with the shotgun.

"They had hits all over their body," Druker said. "He then had them all laying face-down, subdued. These kids weren't going to go at him. He was screaming at them."

In Texas, citizens have the unequivocal right to stand their ground against intruders in their homes. But Druker said that he believes Gonzales' claim of self-defense fell apart because he already had subdued the boys. If they were under Gonzales' control, and no longer a threat, he doesn't understand why Gonzales felt he had to fire the shotgun.

Gonzales said during the trial that he had his gun pointed in the air, but he thought Anguiano, the 13-year-old, was about to lunge at him.

"He perceived this young boy going for his legs," said Alaniz, his lawyer. "He's pointing the weapon, his finger on the trigger, trying to figure out what to do, as he's outnumbered by four intruders. He's giving them orders not to move and one of them lunges. Maybe he was trying to hide, maybe he was trying to grab something, we'll never know."

All that mattered, Alaniz said, was that his client felt at that moment that his life was in danger. He pulled the trigger. The bullet hit Anguiano in the back, traveling through his body and severing his spine.

One of the boys carried Anguiano's bleeding body down the road as they tried to get him to a hospital for help. He was pronounced dead on arrival.

Gonzales stood trial for murder in Webb County. The week-long trial posed the question: How absolute is your right to protect your home, your castle?

"I think the town was split on the use of deadly force," Alaniz said about the case. "For some people it is absolute. You have every right to protect yourself from intruders. But the other side said, this is a defenseless boy on his knees. Why did you have to shoot him in the back?"

Druker said he believed Gonzales took things too far, acted like a vigilante and only claimed self-defense when faced with charges.

He said a medical examiner testified that there was no way the boy could have received the wound he did if he had lunged at Gonzales. And, Druker claimed, Gonzales never mentioned the boys lunging at him or fearing for his life until he got a lawyer.

"This guy subdued them, beat them, had them on the ground," Druker said. "This guy executed that kid. You can't take it that far."

But the defense said it was unfair for anyone to judge whether Gonzales should have shot the boy. His lawyer acknowledged that on the surface, Gonzales' actions seem unreasonable.

"At first glance it looks like an execution," Alaniz said. "But until you are in a life-and-death situation, nobody knows how they are going to react. His perception was his life was in danger. This teen was going to knock him on his back, he would be outnumbered, and then perhaps the one that would end up being buried was Mr. Gonzales."

A jury deliberated three hours before acquitting Gonzales. He spoke in Spanish to reporters after the trial, saying that at the end of the day it was his life or the boy's.

The verdict shocked Druker. He needed to know why the jury agreed to acquit. He spoke to the jurors officially, and then again afterward when he saw them around town. He said he always heard the same answer: They feared losing the right to protect their own homes.

"They said, at the end of the day we can't let these kids think they can come into our house and do that," he recalled. "It was sending out a statement. It was the idea of 'If you come into my home you're dead. At least, in Texas.'

"It was the statute on trial, not Mr. Gonzales. They chose to say it's absolute, and we won't question people when they are where they are allowed to be."

Alaniz said that while he felt the jurors returned the right verdict, he understood the murky nature of the case. It's a tough issue, he said, and it is about perception becoming reality when you fear for your life.

"Nobody wins in these cases," he said. "We have an unnecessary death of a young boy, and a law abiding citizen put through a legal battle to fight for his life in a court of law. It was a tragedy all around."

Giving Chase

Proponents of Florida's Stand Your Ground law say it was never intended to apply to people who pursue someone and then use deadly force. "There's nothing in the statute that authorizes pursuit, confrontation or provocation and altercation," said Rep. Dennis Baxley, one of the sponsors of the 2005 law.

"Everything in this statute says, 'Defend yourself if you are a law-abiding citizen,'" he added. "We stand by you and the presumption of the law is with you."

But how much on the defensive was Greyston Garcia when he chased a suspected thief for a block and confronted him before killing him early on the morning of January 25, 2011? Where should authorities draw the line?

Police arrested Garcia, and prosecutors believed they had enough evidence to charge him with second-degree murder. But a judge dismissed the case late last month, citing Stand Your Ground.

Prosecutors are appealing the decision, and nobody is commenting at the moment.

But the court file tells enough of the story to show that police, prosecutors and judges continue to struggle to find the line between a justifiable homicide and a case in which someone goes too far.

Unlike the other cases, Garcia's doesn't involve a shooting, but a stabbing.

It began when another tenant told Garcia someone was outside their apartment, stealing car and truck radios. Garcia grabbed a kitchen knife, ran down the stairs and started shouting at the man.

The prowler saw him coming, grabbed a bag of stolen radios and took off running though Miami's Little Havana neighborhood.

Garcia did not call police; instead, he chased the suspected thief, catching up with him about a block away. They scuffled, and the brief confrontation was captured on a neighborhood pharmacy's surveillance video.

The video, while blurry, shows the suspect, Pablo Roteto, swinging a bag at Garcia. He blocked the bag and swung his right hand, stabbing Roteto in the chest.

He later told police he didn't even know he had stabbed the man.

Roteta, 26, collapsed and died in the street, bleeding out from a stab wound that slashed his aorta and pierced a lung. Garcia, unaware the man he chased had died, retuned home and fell asleep.

Assistant Public Defender Eduardo Pereira sought to have the murder charge dismissed, arguing that Garcia's use of lethal force was justified and Stand Your Ground gave him immunity from prosecution. Prosecutor Jennie Conklin argued Garcia did not need to use deadly force because the suspect was running away.

In end, the case rested on the 30 seconds in which Garcia caught up with Roteta.

During a two-day hearing, a medical examiner testified that a blow from a four to six-pound bag of radios could cause great bodily harm, and perhaps even death.

But prosecutors presented facts that didn't seem to support a self-defense claim: Garcia had hidden the knife afterward and he sold the other stolen radios.

Judge Beth Bloom sided with the defense, noting that while prior Florida law required a person to retreat before using deadly force, Garcia "was well within his rights to pursue the victim and demand the return of his property."

"How can it be Stand Your Ground?" the lead homicide detective, Sgt. Everns Ford, told the Miami Herald. "It's on video! You can see him stabbing the victim ..."

He called the decision "a travesty of justice."

Kathleen Hoague, a top prosecutor in Miami-Dade County also was thrown by Bloom's decision.

"We feel the judge abused her discretion," she told the Herald. "The law does not allow for you to use deadly force to retrieve your property."

Whether someone acted in self-defense is a decision best left to a jury, she added.

Baxley, the law's sponsor, defended Stand Your Ground, saying it is sound legislation and that police and prosecutors are working out kinks, as they would with any new law.

"I think if anything, it's more a learning curve on how to apply it that's developing," Baxley observed. "You'll always have cases that are a close call."

The human toll

Stand Your Ground has turned the language of law enforcement on its head. Who are the victims? Who are the aggressors?

The police report in the Workman case refers to him and his wife as "the actual victims," even though some might call Rodney Cox the victim. He didn't steal anything or raise his hand -- and lay dead on the floor of an RV.

Perhaps, everyone is a victim in some way.

In each of the four cases CNN examined, split-second decisions carried tragic consequences -- for everyone. Families of the dead agonize over the "what ifs." The shooters feel remorse but are resolute in the belief that the law is on their side.

In Arizona, a family raised a special needs son with extra care, only to lose him after a dispute at a fast-food restaurant. A few blocks away, a father worries that his son will be arrested and vilified like he says George Zimmerman was.

In Texas, a boy will never grow up, and a homeowner has to live with the consequences of taking a life to stop a group of teenagers from stealing snacks.

In Florida, a working man from out of town never returned home because he was mistaken for a prowler. A retired couple was pushed into the limelight by politics and a law they never sought.

And a bag of stolen car radios worth practically nothing cost a Florida man his life. The man who stabbed him doesn't know whether prosecutors will succeed in charging him.

Laurie Levenson, the Loyola Law School professor, said the criminal justice system will sort out the issues presented by the individual cases, but added, "The bigger issue of what America is going to do about its love-hate relationship with guns deserves our attention."

Those who mourn loved ones say there always was another, less extreme option. Lashing out with a gun, a knife, or a bat only escalates a bad situation into a violent one.

Terri Lavery, whose brother was killed by Workman, says she owns guns and knows how to use them. But Stand Your Ground, she adds, is "a bad, bad law that gives people an excuse to just blow people away. Fire now and deal with the consequences later. It's a bad law because it is based on lies and half-truths."

She said she thought she had forgiven Workman and made her peace. But the Trayvon Martin case stirred up old emotions, and now she isn't sure she can ever forgive.

Across two time zones, the family of Daniel Adkins Jr. also struggles to find compassion for the man who shot him, even if they think he was wrong and should be prosecuted.

There were so many other options, Adkins' father said. "He could have driven away. He could have rolled up his window and called police.

"This is a young kid, who made a horrible decision," he added. "I hate his actions, but I don't hate him."

It isn't easy on those who sling the guns or swing the knives, either.

The father of the young man who shot Adkins says the family feels a heavy burden every day, even if his son hasn't been charged with a crime.

He hasn't slept well since the shooting and his son literally is sick over killing someone - throwing up whenever he thinks about it.

But that doesn't change the fact he was doing what the law allowed him to, his father is quick to add.

"I feel bad, I feel sorry for this family," he said. "It's a real bad situation. But the days we live in, you can't just go attacking nobody's car at 8 o'clock at night when it's dark at a drive-thru."

James Workman, whose case launched the Stand Your Ground movement, feels the same way about Rodney Cox.

"Of course I'm sorry I had to shoot him," Workman said, a tear forming in his eye. "I didn't want to shoot him. I wanted him to leave."

Workman said he wouldn't hesitate to shoot again if the circumstances were the same. "It wouldn't make any difference to us what the law was," he said. "How many people do you know who wouldn't do everything they could to protect their wife?"

He favors Stand Your Ground, with limitations. And that's really the key issue raised by this sweeping change in the nation's gun laws: Where should the line be drawn?

"I think people ought to be able to protect themselves," Workman said. "I don't think they ought to be able to go looking for trouble."