What Happened to Mary Ann Gene Groves — and Why Did Her Grandson Kill Her?

In Netflix's popular series I Am A Killer, you get exactly what you came for. Each season centers around a handful of individuals who are in prison for murder. It's a fascinating and sympathetic look at a heinous crime that is often left unexplored by other documentaries and series.

Some of the prisoners regret their actions while others truly believe they did the right thing. In between those two reactions, is a gray area that consists of shame, rage, sadness, and remorse.

In Season 5 we meet Rex Groves, who is serving a 46-year prison sentence at Putnamville Correctional Facility in Greencastle, Ind. He will be eligible for parole in 2029. The first thing Rex says is that regardless of what he does with his life, some people will always look at his past. He wants to be clear about one thing, Rex doesn't think he is a monster. His victim might disagree. What happened to Mary Ann Gene Groves? Details to follow.

Rex's childhood was filled with abuse and abandonment. After his older brother died, Rex's mother turned to drugs and alcohol in order to cope with the grief and the pain.

She would often disappear for days or weeks at a time. His father was physically violent and according to Rex, would beat him. These violent outbursts were then confusingly blamed on Rex's mother as if she was somehow responsible. When he needed refuge, Rex went to his grandmother's house.

Mary Ann lived in the same trailer park as Rex's father, but she couldn't have been less like her son. Rex described his relationship with Mary Ann as "exceptional" due largely to the fact that she was always happy to see him. "She was my barrier between me and everybody," he explained.

His grandmother was always happy to see him, which was a stark change from his home.

In his 20s, Rex started drinking and using drugs. Like many people, he was a frequent user of marijuana before graduating to cocaine, mushrooms, and acid. He liked drugs because they helped him stop caring about his life. Soon, drugs and alcohol became his entire life. He was rarely sober. Rex became increasingly paranoid as his drug use increased.

He often thought about killing people he believed were after him.

On Dec. 10, 2007, Rex was in a particularly angry mood. In the docuseries, Rex revealed that he was thinking about the many ways in which life had failed him, and he was suddenly filled with rage. He claimed he tried to soothe the savage beast using Xanax, alcohol, and weed, but it "didn't seem to be working." The hate couldn't be quieted.

"I felt like everything that was going wrong with my life was because of my past, and my past was because of my family."

Rex headed over to his father's trailer with the intent of killing him. At the last minute, Rex decided to go to his grandmother's house in an effort to find some sort of peace. That is not what happened. It's unclear what set Rex off but the next thing he knew there was a set of shearing scissors in his hand.

"She never stood a chance," he said. He stabbed Mary Ann repeatedly and watched her body until she was dead then carried her body to bed. Rex fell asleep next to his grandmother's body.

The following day, Rex confessed to murdering his grandmother. In a video recording of his confession, Rex is explaining to the police officer that he felt as if he was outside of his body looking in. He couldn't stop, and didn't understand why he was killing Mary Ann. He was also laughing in a strange, nervous fashion. The investigators decided he needed to see a mental health professional.

When Rex was initially evaluated, he was diagnosed with schizophrenia and was declared legally insane at the time of the murder. When he was assessed again, this doctor disagreed.

"Insanity is a legal concept, not a clinical concept," said Dr. Don Olive who was appointed by the Cass County Superior Court to evaluate Rex. Dr. Olive saw no evidence of psychosis and diagnosed Rex with borderline personality disorder as well as anti-social personality disorder.