Army sergeant's death uncovers secret affair, murder plot concocted by wife, lover

On New Year's Eve 2018, Army Sgt. Tyrone Hassel III was shot, multiple times, as he stood near his vehicle in the driveway of his father’s home in Michigan, where he was staying with his wife and their almost 2-year--old son.

The shooting prompted a panicked 911 call from Hassel’s wife, Army Spc. Kemia Hassel, who was inside the home at the time.

Jaramee Peppers, one of the St. Joseph Township Police officers responding to the scene, told "20/20" he remembered Kemia Hassel being emotionally distraught as her husband was dying.

"We were lifting the gurney onto the back of the ambulance that got him in there, and I stepped back .... she's going past me and trying to climb into the ambulance," Peppers said.

But as investigators started probing the 23-year-old's murder, they would find out that Kemia was actually hiding a dark secret: She and a secret lover concocted the plot to kill her husband from their base.

A "20/20" airing Friday, Feb. 16, at 9 p.m. ET and streaming on Hulu the next day explores the case and investigation that led to Kemia being sent away for life. The show includes interviews with key investigators and family members who said they were shocked when they learned the truth about Kemia.

Tyrone Hassel Jr, the victim's father, told "20/20" that his son decided to enlist in the military while he was in college.

"He was motivated to do better. He lived here and he knew it wasn't nothing here, nothing going on," Hassel Jr. said.

In 2015, Sgt. Hassel met Kemia in the Army while they were at Fort Carson in Colorado and their relationship quickly became serious.

"When I heard of his relationship with Kemia, he was getting engaged," Hassel Jr. recalled.

Kemia would soon have a son and the Hassel family said she had a good relationship with them.

At the time of Sgt. Hassel’s murder, Kemia and Sgt. Hassel were on block leave from Fort Stewart in Georgia, where Specialist Kemia Hassel worked as a truck driver and Sgt. Hassel worked as a wheel mechanic.

After Sgt. Hassel was killed, the family said they came together to help Kemia as she mourned.

"Most of the day she would just sit on the couch and wouldn't move, wouldn't go nowhere," Hassel Jr. said.

Police said Kemia cooperated with the investigation, speaking with police multiple times. On New Year’s Eve, Kemia said she stayed at home with their young son while Sgt. Hassel was at a family party.

During one interview with police, Kemia was asked if Sgt. Hassel had life insurance and she mentioned she was going to receive a $400,000 from the Army after her husband's death.

She repeatedly told officers she had no idea who would target her husband.

Investigators had a couple of clues, including a neighbor who noticed a man get into a black car right after the shooting.

Eleven days after Sgt. Hassel's killing, the investigation took a dramatic turn when police received an anonymous tip from a woman.

The woman claimed that her son was in the military and that her son knew Kemia was having a relationship with another soldier.

"She didn't really elaborate too much on that, but she did hint that there was a relationship that Kemia was involved in that may have led to something like this," Peppers said.

According to the St. Joseph’s Township Police Dept, the same day that call was made, two soldiers at Fort Stewart came forward to the Army’s Criminal Investigation Division (CID) with fear about one of their friends, Spc. Jeremy Cuellar, who drove a truck on the base.

Spc. Jaquan Hamilton told investigators he was aware of a relationship between Kemia and Cuellar that was kept from her husband and that he was feeling anxious about his own safety.

The Army Criminal Investigation Division (CID) immediately launched its own investigation and conducted multiple interviews with soldiers who knew Kemia Hassel and Jeremy Cuellar.

Special Agent Zachary Roberts of the Army (CID), told "20/20" that a friend of Cuellar’s said that "Cuellar stated that Kemia Hassel was his girl and that Sgt. Hassel had to go."

The CID investigators learned that Sgt. Ta'Darius Gholston had sold Cuellar two guns prior to the shooting, one of which matched the caliber used to kill Sgt. Hassel. They also learned that Cuellar had allegedly described to Hamilton how he said he killed Sgt. Hassel.

"He's telling his best buddy on base what he did; after he'd shot him, he stood over him and put one in his head to confirm the kill, one of the shots was directly in the forehead," St. Joseph Township Police Sgt. Mike Lanier, one of the investigators on the case, told "20/20."

Cuellar was put under CID surveillance at his home near the base. Cuellar's black Chevy Impala was searched and investigators found 9-mm. ammunition and another 9-mm. magazine, which matched the type of caliber ammunition that was found at the crime scene.

CID provided Michigan investigators with the plate of the car and the Michigan team found out the car was in the area during the time of the shooting.

Cuellar was arrested on Jan. 11, 2019, but refused to speak with officers.

That same day, back in Michigan, investigators brought Kemia back in for questioning.

Kemia denied that she was involved with Cuellar multiple times despite the officers confronting her claiming knowledge of her affair with Jeremy Cuellar.

Kemia was asked to take a polygraph test and she agreed. After being told she was lying, Kemia Hassel was interviewed again and finally confessed.

Kemia opened up to investigators and admitted she had an affair with Cuellar and gave details about her role in her husband's murder.

She signed a police document admitting to plotting to kill Sgt. Hassel and was arrested on Jan. 12, the day of her husband's funeral.

The Hassel family said they were in shock.

I couldn’t believe it," Ashanti Hassel, the victim's stepmother, told "20/20. "I was kind of angry because I sat there with [Kemia], and we catered to [Kemia] for 12 days."

While in jail, Kemia called her mother and admitted to the plot to kill her husband. The conversation, which was recorded by the jail, was used as evidence in her criminal trial.

Prosecutors would also use cell phone records that they said showed Cuellar and Kemia were communicating in the hours leading up to the shooting.

Kemia's attorney Chris Kessel contended his client was coerced by Cuellar into going forward with the murder plot.

"There's no doubt in my mind that had Kemia never met Jeremy Cuellar, this never would've happened," he told the jury during the trial.

Cuellar contended that Kemia called him and asked him to come back to the house when she confirmed her husband was returning to bring food.

Kemia was convicted on July 18, 2019, of first-degree premeditated murder and conspiracy to commit first-degree murder.

On Aug. 29, 2019, she was sentenced to life in prison without parole.

Cuellar pleaded guilty to second-degree murder on July 30, 2019, and was sentenced to 65 to 90 years in prison. He later requested to withdraw the plea, but the Michigan Supreme Court denied to hear his case in 2021.

Kemia and Sgt. Hassel’s son, Tyrone Hassel IV, lives with Kemia’s mother.

Ashanti and Tyrone Jr said they see him via FaceTime. Tyrone Jr. has a message for his grandson,

“I would like him to know that his father was a good man and his father loved him very dearly," he said.