Now authorities say Gleason's new prison buddy is his latest victim, and the inmate's mother is questioning why prison officials didn't take Gleason's threat to kill again seriously.
"You knew this man threatened to kill, and you gave him the opportunity to kill my son," Kim Strickland said in an interview days after her son, 26-year-old Aaron Cooper, was killed.
Cooper told his mother he and Gleason talked about God and other things to pass the time in the segregation unit at Red Onion State Prison, a supermax prison in the mountains of southwest Virginia. Gleason gave him stamps and paper to write home, and Gleason even wrote to Strickland asking her to be his pen pal.
"I don't want you thinking that I'm talking with a Satan worshipper or the boogeyman," Cooper wrote to his mother on June 24. "He's just another guy locked up."
Just over a month later, prosecutors say Gleason lured Cooper to the thick chain-link fence dividing their cages in the recreation yard on July 28 saying he had a gift: a gang necklace. Instead, it was a noose fashioned from torn bed sheets that he used to strangle Cooper, Wise County Commonwealth's Attorney Ron Elkins said.
Gleason, 40, is scheduled to be sentenced Aug. 31 for killing another cellmate, Harvey Watson Jr., last year. Gleason already was serving a life sentence then for killing another man in 2007. Elkins said he likely would wait until after the sentencing later this month to charge Gleason with Cooper's death.
But Strickland, like some of Watson's family members, said she does not want Gleason to get the death penalty - not out of mercy, but because being executed is what he wants.
"If he wanted to die, why didn't he commit suicide?" said Strickland, clinching her fists and gritting her teeth, her voice rising. "Why do we have to kill him?
"They're going to have to make new provisions to keep that man, but he should rot in prison, die in prison. That's where he belongs."
Strickland questions why guards didn't stop her son's death. Prisoners in segregation at Red Onion are isolated except for one hour a day, when they are placed in separate outdoor cages for recreation.
Elkins said a seemingly unsuspecting Cooper helped Gleason slip the end of the noose through the fence and place it across his neck. Elkins said guards noticed Cooper was dead when they came to return Gleason to his cell, but he said he did not know how long Cooper had been dead.
Prison officials refused to comment on the death or to answer questions regarding how many guards were watching Gleason, Cooper and three other inmates who were at recreation when Cooper was killed, citing the ongoing investigation and safety concerns.
In the previous case, Gleason fired his attorneys and pleaded guilty to killing Watson days before his June 1 trial. He told prosecutors he would kill again if they didn't seek the death penalty in his case.
"I murdered that man cold-bloodedly. I planned it, and I'm gonna do it again," Gleason told The Associated Press in May. "Someone needs to stop it. The only way to stop me is put me on death row."
Gleason said he begged correctional officers to move Watson, who suffered from mental illness and sang, screamed profanities and masturbated in the 8-by-10-foot cell they shared at Wallens Ridge State Prison for seven days.
On the eighth day - May 8, 2009 - correctional officers found Watson bound, gagged, beaten and strangled. His death went unnoticed for 15 hours because correctional officers had not followed proper procedure for inmate head counts at the high-security prison.
Gleason was moved to Red Onion after Watson's death. He remains there in segregation.
Cooper, who his mother said also suffered from bipolar disorder and ADHD, was serving 34 years for a string of robberies and carjackings. He was sent to Red Onion after starting a fire at another prison.
Cooper spent much of his childhood in and out of psychiatric facilities while Strickland, a single mother who worked as a barber, struggled to make ends meet. Cooper joined the Crips street gang and was locked up not long after his 21st birthday.
Strickland said she was shocked when she found out Gleason was involved in her son's death less than a month after writing to her. She had written him back, asking about his past.
"First of all, I'm not looking for a sugar mama. I have my own money," Gleason wrote to Strickland on June 30. "I'm just looking to write someone because after I got my time I cut everyone off because I put them threw (sic) enough."
Strickland said she would like to visit Gleason in prison so she can ask him why he targeted her son. She also wants answers from corrections officials, who have told her they can't answer her questions because of the ongoing investigation.
"I promised my son when I saw him (to identify his body), if it's the last breath in my body, whoever did this and allowed it to happen, I would see them brought to justice," she said.