CHICAGO (STMW) — A clinical neuropsychologist testified Wednesday that alleged cop killer Marcus Floyd does have “retrograde amnesia” as he claims.

Robert Hanlon said when he interviewed the 24-year-old Floyd at Cook County Jail, he noticed that Floyd showed signs of having “memory impairment.”

As other mental health experts have found, Floyd has no recollection of the night Chicago Police Officer Thomas Wortham IV was murdered, according to Hanlon, who was hired by defense attorneys.

“Retrograde amnesia” is a legitimate condition and can develop after anoxic brain damage, which Floyd suffered while he underwent surgeries for his gunshot wounds in the May 19, 2010 incident, Hanlon said

Floyd was severely injured in a shootout in which Wortham’s father, a retired Chicago Police sergeant, fired at Floyd and his cohorts after they tried to take the younger Wortham’s motorcycle, prosecutors said.

Floyd’s cousin, Brian Floyd, 20, was killed in the gun battle at 85th Street and Martin Luther King Drive.

The lookouts in the deadly crime — Paris McGee and Toyious Taylor — are serving life sentences for Wortham’s murder.

Defense attorneys, who are asking a jury to find Marcus Floyd unfit for trial, presented videotaped recordings Wednesday of Floyd being interviewed by Hanlon.

Marcus Floyd could be heard answering Hanlon’s questions very slowly and sounding confused at times.

During Wednesday’s proceedings, prosecutors asked their witness, forensic psychologist Christofer Cooper, back on the stand.

Cooper said when he evaluated Marcus Floyd, his demeanor and speech was more “logical and coherent.”

“His speech was conversational and fluid. … It was a conversation I’d have with a friend,” Cooper said.

Cooper agreed with the prosecution’s contention that Marcus Floyd may have altered his behavior because he knew he was being videotaped when he was with Hanlon.

They maintain that Marcus Floyd can be tried for murder because he knows what he is charged with and can work with his attorneys to build a defense.

Closing arguments in Marcus Floyd’s fitness hearing are expected Thursday morning before Judge Timothy Joyce.

(Source: Sun-Times Media Wire © Chicago Sun-Times 2015. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)