A receipt from Target, a stolen car in Mexico and a third unsolved murder: Investigation into yacht murder of California couple Hawks worked for decades toward their dream - then, strangers took it all away.

Tom Hawks, a Vietnam veteran and father of two boys, had a beautiful dream: to retire in his 50s and live on a boat with his wife Jackie. He eventually achieved it after prudently saving and investing his money for decades. But over the course of a week, another couple — complete strangers to the Hawks — took it all away.

After planning for years, Tom and Jackie Hawks eventually bought a 55-foot trawler yacht for about $300,000 and named it the “Well Deserved,” which their tight-knit circle of friends and family agreed was perfectly fitting.

The couple outfitted the vessel with the latest technology and for two years traveled from their Newport Beach mooring along the California coast and to Mexico. Then, when their younger son, Matt, told them he and his wife were going to have a baby, they decided to sell the boat and get a house back on land to be closer to their grandchild.

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On November 12, 2004, the couple took their last trip to Santa Catalina Island off the coast of Los Angeles, California, to commemorate their passion project’s imminent sale. By this time, Tom and Jackie Hawks had told family and friends that they’d found a buyer and that the sale was going to take place in the next few days.

“Next thing you know is, no one could get a hold of them,” their son, Ryan Hawks, told “20/20.” “For them just to shut off their cell phones and drop off the face of the earth is...extremely out of character.”

The family found the Well Deserved moored in its usual berth at Newport Beach but the couple and their car — a silver Honda CR-V — were nowhere to be found.

“My uncle knew something was…wrong right away,” said Ryan Hawks, adding that his uncle had noticed the dinghy his parents used to get to their yacht hadn’t been tied properly to the dock and its motor hadn’t been lifted from the water. “My uncle was a hundred percent positive that my dad didn’t leave the boat that way.”

Tom Hawks’ friend Don Trefren also noticed things were out of place on the yacht.

“I noticed that the tarps up above on the deck, on the flying bridge, were all off. All the controls were just kind of peeled back and there was a towel hanging out one of the portholes,” Trefren told “20/20.” “I got a sick feeling in my stomach, you know, just like, just a sick feeling that something wasn't right.”

The receipt from Target

The couple’s tight-knit group of friends and family knew Tom and Jackie Hawks had gone with the prospective purchaser to take the boat out for a test ride. They also knew that the buyer of the boat was likely the last person to have seen them.

Jim Hawks, Tom Hawks’ brother and a retired police officer, left a note on the Well Deserved with his phone number in hopes that the buyer would contact him.

It was Jennifer Deleon who called him back, telling him she and her husband Skylar had paid for the boat with cash in full. Still suspicious, Jim Hawks reached out to Trisha Schutz, a friend of the family who managed the missing couple’s finances while they were traveling.

“Tom and Jackie, if they would have sold that boat, they would have deposited that money into their bank account,” Schutz told “20/20.” “There was no activity on their account. So we knew that something was really wrong. [Jim Hawks] told me that he was gonna contact the police department and file a missing persons report.”

Newport Beach police took on the case once a missing persons report was filed, nearly two weeks after the couple’s disappearance.

“This couple…were in the process of selling, or sold a vessel to this other couple, Skylar and Jennifer Deleon,” Newport Beach Det. Sgt. Dave Byington, now retired, told “20/20.” “Skylar happens to be a convicted felon. He's on probation. I go, ‘Geez… OK, well this doesn't sound good right now.’”

Skylar Deleon had a troubled childhood. He had been a child actor, with one of his most prominent roles as an extra in the 1990s TV show “Power Rangers.” Later, he met Jennifer online, got married, and had a little girl. He was expecting another child with her at the time that the Hawks went missing.

Jennifer, a hairstylist, was the breadwinner for the family while they lived in a converted garage behind her parents’ home in Long Beach. Given their living situation, the couple did not seem to police like buyers of such an extravagant yacht.

Police searched the Well Deserved, where they found a receipt from Target. The purchase, which was dated two days after the day friends said the Hawks were taking the prospective buyer for a test ride, listed trash bags, bleach and the antacid Tums.

“If I was going to kill somebody, I'd have my clean kit. And it would be bags to get rid of evidence, bleach to wipe down the scene and maybe, if I had a conscience, some Tums to settle my stomach after killing some poor people,” Byington said.

Target was able to provide surveillance photos of the purchaser to police. But investigators, who expected to see Skylar Deleon buying the supplies, were surprised to find Steve Henderson, Jennifer Deleon’s father, in the photos instead.

Police learned Jennifer Deleon sent her father to buy the bleach, Tums and trash bags so the couple could help clean their new boat. Henderson pointed investigators to a nearby church that he said the couple was helping to clean.

“When I see a family volunteering in a church, I was put at ease a little bit with that, thinking, ‘OK, this is going to turn out OK. The Hawks are fine,’” Byington said. “I was talking to Jennifer and basically said, ‘We're looking for the Hawks. The family's very concerned.’ And she said, and she was very genuine, she goes, ‘We're really concerned, too.’”

“Then she goes, ‘We've been trying to reach out to them continually since we bought it.’ She said they have a lot of property, clothes and stuff. ‘We don't know what to do,’” Byington continued. “She was very specific and seemed very genuine in her concern for the Hawks and finding them. Skylar…proceeded to tell me the same thing that Jennifer did.”

Skylar Deleon produced paperwork for the boat’s purchase, complete with signatures, fingerprints and a notary public’s certification.

Much to their surprise, Skylar Deleon openly admitted to police that he used drug money to buy the vessel.

“At this point, I already knew that Skylar was on probation for armed burglary, so he's a felon,” Byington said.

“‘I'm telling you, Sergeant, I want to go straight with my family. I'm a father now. I have another child on the way and I want to do the right thing. So I'm trying to invest this money in a way that I can support them,’”Byington said Deleon told him.

Deleon told police that on Nov. 15, 2004, he paid the couple for the Well Deserved, presenting them with a briefcase full of cash in the parking lot near the moored yacht. Deleon said that his wife, child, a notary public and a friend from Mexico, Alonso Machain, were also there for the transaction.

“According to Skylar, Tom [Hawks] asked him, ‘Is it all here?’ Skylar kind of giggled at me and said, ‘Yep, it's all there.’ And so they basically said, ‘Here's the keys to the yacht,’” Byington said. “Tom and Jackie drove off in the Honda and Skylar and Jennifer said that was the last time that they saw them.”

The 1998 silver Honda CR-V

Nearly a month after his parents vanished, Ryan Hawks was urged by his uncle to go to the media to ask the public for help after investigators hit a dead end.

A retired couple in San Miguel, Mexico, heard his plea, telling police that they saw the missing couple’s 1998 silver Honda CR-V parked next to a mobile home.

The mobile home’s owner told Mexican authorities he didn’t know Tom or Jackie Hawks, but that the car was given to him from a friend: Skylar Deleon.

“And at that moment…any possibility that the Hawks were still alive died right there, unfortunately,” Byington said.

Caitlin Rother, a consultant for “20/20” on this story and author of “Dead Reckoning” about this case, said with the discovery of the car, police “realized that Skylar Deleon and Jennifer, who is also described [by others at the mobile home park], had been down there.”

“They had, now, witnesses who knew them and [the witnesses] said, ‘[The Deleons] gave us this car,’” Rother said.

“Skylar murdered these people,” Byington said he concluded after finding the Hawks’ car. But investigators still didn’t have enough to prove it.

On Dec. 17, 2004, police arrested Skylar Deleon on money laundering charges while they continued investigating him for the murder of the Hawks.

Investigators searched the Deleon’s home, finding the Hawks’ laptop and their video camera, which the Deleons used to document the Thanksgiving that the Hawks never got to spend with their family.

For months after Skylar's arrest, Jennifer Deleon continued to insist on her husband’s innocence in the Hawks’ disappearance, even declining an offer of immunity in exchange for information as to the whereabouts of the Hawks.

A third murder

Newport Police discovered another interesting clue in the Deleon’s home – a business card for Los Angeles Police Department Det. Joe Bahena, who worked as a liaison with Mexican police. They found that Bahena was helping Ensenada State Police investigate the case of Jon Jarvi. Jarvi had been found murdered with his throat cut in Mexico in 2003.

Jarvi met Deleon while the two were serving time at the City of Seal Beach jail, where some inmates were allowed to go out during the day on work release. After Jarvi was freed, he stayed in touch with Deleon, who promised him a big score.

In December 2003, a year before the Hawks’ disappearance, Deleon sold Jarvi on a business proposition to make a large sum of money – Jarvi gave Deleon $50,000 in cash, then accompanied Deleon to Mexico where he was supposed to complete the big score Deleon told him about. Jarvi never returned.

“There never was any deal in Mexico,” Jeff Jarvi, Jon’s brother, told “20/20.” “He took my brother down there with, specifically with the role of murdering him.”

Mexican police questioned the Deleons at the time, but Jarvi’s case remained unsolved until Newport Beach detectives started working the Hawks case.

The dominoes fall

Kathleen Harris, the notary who certified the paperwork for the sale of the Well Deserved, was interviewed by police several times. She repeatedly denied that anything was amiss, until the day she came clean.

“She came in and she said she'd never met Tom and Jackie Hawks. She had nothing to do with the murder,” former Orange County prosecutor Matt Murphy, now an ABC News consultant, said. “She was given documents and paid in cash to backdate the documents. And so she backdated them to Nov. 15, which was the day that they went missing.”

“That was the first domino to fall,” Byington said. “Then we started pressuring everybody else because we knew everybody else had lied to us, too.”

Alonso Machain was the next to reveal his role in the murder. He told police that he first met Skylar Deleon when he was a jailer at the City of Seal Beach jail. Machain admitted he took part in the murders and revealed the full scope of the murder conspiracy to investigators.

Machain said Skylar Deleon convinced him that Deleon was an international hitman and that he needed to take out Tom and Jackie Hawks because they were evil.

Machain told police that on November 15, 2004, he, Skylar Deleon and another accomplice, John Kennedy, set out toward Santa Catalina Island on the Well Deserved with Tom and Jackie Hawks on a “sea trial,” or a test run of the boat.

Machain said Skylar Deleon and Kennedy overpowered Tom Hawks and handcuffed him, while Machain subdued and handcuffed Jackie Hawks. Machain said he, on Deleon’s orders, taped over the couple’s eyes and mouths and tied them together as Deleon navigated the boat toward the deepest point of the sea. Machain said they then tied the couple, handcuffed, to one of the yacht’s anchors – then Deleon threw the anchor overboard and it dragged the couple over the side.

Jennifer was not on the boat during the murders. So it came as a surprise to many when she, too, was arrested, just weeks after giving birth to her second child. Investigators discovered that Skylar and Jennifer spoke by phone numerous times on the day Jon Jarvi was murdered, and again when the Hawks were killed.

“That woman was physically not on the boat during the murders, but she was absolutely on the boat with guidance in spirit,” said Matt Murphy.

Machain testified in three separate trials against Jennifer and Skylar Deleon, as well as Kennedy. In a deal with the prosecution, he pleaded guilty to two counts of voluntary manslaughter and was sentenced to 20 years and four months in prison.

In 2006, Jennifer Deleon was convicted of the murders of Tom and Jackie Hawks and later sentenced to two life terms without the possibility of parole. She was charged in connection to Jarvi’s murder, which she denied any involvement in. In a preliminary hearing before her trial for the Hawks’ murders, a judge dismissed that charge.

Nearly two years later, Skylar went to trial for the murder of Tom and Jackie Hawks and Jon Jarvi. He was convicted of all three murders.

John Kennedy was also convicted of the Hawks’ murders, and like Skylar Deleon, sentenced to death. Both remain on death row today.

“At the end of the day, they all get what they deserve,” Byington said. “Only Alonso [Machain] will ever see the light of day again. He got sentenced to 20 years and he actually will be out soon.”