Arlington homicide detectives are busy investigating four murders that have taken place in the span of a week.

Early Monday morning, the body of a man was found inside a car parked in the back parking lot of No Frills Grill and Bar on Little Road.

Police said the man, identified by the Tarrant County medical examiner as John Ross Shreves, was dead from an apparent gunshot wound to the head.

According to Tiara Richard with the Arlington Police Department, the driver's side window was shattered and that the man's death is being investigated as a homicide.

Shreves was an English teacher at Kennedale Jr. High School, according to the district. He had been with the district for three years, the last two in his current position. Shreves was a 2004 graduate of Kennedale High School. After high school he attended college at Southwestern University in Georgetown before graduating in 2008 from the University of North Texas, according to his web page on the district's web site.

Police are interviewing patrons of the bar to find out more information and to narrow down a time frame of when the shooting took place as well as a possible motive.

Anyone with information is encouraged to call Det. Seth Archer at 817-459-5336 or, to remain anonymous, call CrimeStoppers at 817-469-8477. Through CrimeStoppers, tipsters may be eligible for a reward of up to $1,000 for information leading to an arrest and indictment.

Just hours earlier, less than two miles from the bar, police found a woman dead inside her home on Wild West Drive.

The woman's family had requested police do a welfare check after the woman did not return phone calls to the family.

When officers arrived, no one answered the door, Richard said. Officers walked around the home and saw a person inside the home not moving and not responsive. Officers entered the home and found the woman, whose name has not yet been confirmed, deceased with obvious signs of trauma.

The woman's death is being investigated as a homicide, police said.

Officers said it did not appear that anyone forced their way inside and they are working to determine if anything was taken from the home.

Neighbors said they could not understand why someone would kill the woman.

"I'm sick, it's just horrible," said Paula Moon, one of the woman's neighbors. Moon also told NBC 5 that the woman recently had some contract work done on her home and that "she left a note on my door about a nice man who would do my trees."

Homicide detectives in Arlington are still working to solve two other murders that took place earlier this month.

Grandmother's Murderer Still on the Loose

Arlington police are also continuing to investigate the murder of grandmother Leona Swafford, who was carjacked, abducted, and killed by an unknown man on June 4. The 83-year-old's body was dumped outside another home just hours after she was carjacked in her own driveway. Her vehicle was found in an apartment complex parking lot about an hour later.

Investigators said they are still trying to determine a motive and if it was a random crime or something else. Police said they are withholding some information that only the killer would know in hopes of it leading to an arrest.

Arlington police describe the attacker as a black man in his late 20s to late 30s with a muscular build, standing 5 feet 11 inches to 6 feet tall with short hair that is possibly a half-inch afro. He has little to no facial hair and was last seen wearing a light-colored shirt and blue jeans.

Authorities are urging the public to look for someone who not only fits the description but exhibits abnormal behavior, such as acting nervous, unexpectedly leaving town, not showing up for work or showing great interest in news coverage of the case.

Arlington police have released a composite sketch of the attacker based on witness statements.

Anyone with information on Swafford's abduction is asked to call 817-575-8529.

Oak Farms Dairy is offering a $10,000 reward for information that leads to an arrest and grand jury indictment.

Police say they plan to pursue capital murder charges when they make an arrest.

19-Year-Old Shot Outside Home

Additionally, a homicide investigation continues for a 19-year-old man that was fatally shot in front of his home on June 5.

Witnesses told police that Donsha Hughes, 19, was called by an acquaintance and instructed to meet him outside. The family of Hughes said they heard gunfire minutes later and took the injured Hughes to an area hospital where he later died.

Detectives in that case are still looking for the person involved in the shooting.

Arlington police said anyone with information about any of these incidents should contact the police department at 817-274-4444.

NBC 5's Kendra Lyn and other NBC 5 staffers contributed to this collective report.