A Cobb County man who helped plan a “hit” on his roommate during the summer of 2018 has been sentenced to life in prison.

A jury found Santos Tomas Vasquez, 43, guilty of malice murder, aggravated assault and armed robbery Wednesday following a three-week trial.

Superior Court Judge Ann B. Harris followed up the verdict by handing down the life sentence, Cobb District Attorney Flynn Broady Jr. announced in a news release Thursday.

According to Broady, Vasquez and three other men hatched a scheme to kill Vasquez’s roommate, 33-year-old Andres Meza Munguia, in July 2018. Court records show Vasquez arranged several meetings with his co-conspirators — Dorian Acosta, Anthony Lopez and Fredy Jimenez — in the days leading up to the homicide and they planned Munguia’s execution.

After Vasquez and Jimenez drove Acosta and Lopez to the Austell residence early the morning of July 29, Jimenez opened the door to let Acosta and Lopez in. They shot Munguia to death as he slept on the couch, then the four men fled the scene.

Vasquez and Jimenez waited about an hour to return to the home and pretended to discover the killing. Vasquez called police to report the homicide and told authorities he had no idea what happened.

He was arrested days after the shooting and spent more than four years in jail awaiting trial with no bond, online booking records show.

Cobb police officers and U.S. Department of Homeland Security agents investigated the slaying and used cellphone records, tower data, surveillance video and cellphone extraction evidence to prove Vasquez’s guilt, Broady said.

All three of his co-defendants also pleaded guilty and testified against him during the trial, according to the district attorney.

The motive for the killing remains a mystery, according to prosecutors.

“The jury returned a verdict that spoke the truth — that this defendant was the ringleader behind this heinous murder,” said Cobb Senior Assistant District Attorney Stephanie Green, the lead prosecutor in the case. “He took advantage of and manipulated his co-defendants to slaughter a man for reasons that will never be understood.”