The man accused of killing a Forest Park teen and identified more than a year later in her diary told police he blacked out when the girl was killed.

And in an apology letter Marshae Hickman penned seeking forgiveness for 15-year-old Candice Parchment’s death from her mother, Hickman said he wasn’t in the right “state of mind.”

“I am sorry for what I have done,” Clayton County police Detective Ashley Melvin read in court Tuesday afternoon from Hickman’s letter. “I was in the wrong state of mind and this haunts me every day. I wish I could bring her back.”

Hickman is on trial for allegedly killing Parchment in April 2010 and hiding her body. Parchment was strangled and stabbed, police said, and Hickman returned frequently to the hiding place to confirm her body hadn’t been found.

In an interview recorded by police and played in court, Hickman said he didn’t remember what happened.

“I don’t know what happened,” Hickman said. “I blacked out.”

He told police that he put his arms around Parchment’s neck and she went limp and had no pulse.

Hickman was 19 when he was indicted in 2011 for charges of murder, multiple counts of felony murder – killing a person during the commission of a felony – aggravated assault, false imprisonment, aggravated battery and concealing a death, and is on trial facing life in prison.

He towered above his attorney Ashley Palmer, but spoke no words as she stood to approach the jury and suggest that another name in that diary – that of a witness for the prosecution, Germaine Robinson – might have been guilty of killing Parchment.

“The same motive the state wants to assert that Marshae Hickman had, Mr. Robinson had,” Palmer said.

At the center of the trial, and ultimately one of the things the jury must consider, are the contents of Parchment’s diary that alleged both men, then teens, lured her into an abandoned Forest Park home and tried to sexually assault her in January 2010.

Parchment disappeared the night of April 28, 2010, and her body was found seven months later beneath a mattress in a wooded area behind a Forest Park apartment complex.

The diary, which identified both Hickman and Robinson, eventually led police to the men. But it was nearly a year after Parchment’s body had been found, her mother said.

Tuesday afternoon, Robinson – who pleaded guilty to aggravated assault and is now incarcerated in the Clayton County jail – testified that he was threatened by the much larger Hickman on the day of the rape attempt.

“He told me he wanted me to hit her upside the head with a rake,” Robinson said. “He was like, ‘You either do it, or I’m going to kill you and her.’”

“After that, he said, ‘choke her,’ and I started choking her.”

Police interviewed Robinson in a video shown to the jury, and he described how he thought Parchment might have died … by being either choked or stabbed.

From the stand, Robinson explained how he reached that conclusion.

“He told me to choke her that night (of the rape attempt) and he tried to choke her, and later he told me he was going to stab me,” Robinson said. “So I just put it all together.”

Palmer was incredulous when she pointed out, however, that Robinson seemed to have more information about Parchment’s manner of death than her client.

“Marshae Hickman was unable to come up with some key facts when he described what happened,” she said. “But Mr. Robinson was able to describe to you that Candice was stabbed … and he’s not the suspect?”

Assistant District Attorney Michael Thurston directly asked Robinson what involvement, if any, he had in Parchment’s death.

“None,” Robinson said.

Palmer showed Robinson a truancy report with his name on it from the day Parchment disappeared, then challenged his account of events.

“This document says you were unlawfully out of school on April 28,” she said. “But you had nothing to do with her disappearance?”

Police questioned both Hickman and Robinson. Assistant District Attorney Bill Dixon said Hickman gave police information that corroborated with other evidence they had during a series of interviews.

“He tells where the body was,” Dixon said. “In the end, he confessed that he killed that young lady.”

But Palmer said her client’s confession was a result of intimidation and fatigue following a battery of questioning from a revolving door of officers and investigators.

“When someone is interrogated for six to seven hours over the course of two days, they will comply just to get it over with,” she said.

Testimony ended Tuesday evening and will continue on Wednesday.