BALTIMORE (Map, News) - The inmate accused of killing a fellow convict aboard a Baltimore-bound prison bus shows signs of a slew of mental problems, including schizo-affective disorder, fetal-alcohol syndrome and attention deficit hyperactivity disorder, a psychiatrist testified Tuesday.

Defense attorneys for 24-year-old Kevin Johns want to show Harford Circuit Court Judge Emery Plitt their client was not criminally responsible for his actions Feb. 2, 2005, when he allegedly strangled 20-year-old Phillip Parker, Jr.  aboard a Department of Corrections bus.

Dr. David A. Williamson, a psychiatrist specializing in violent criminals and husband to defense attorney Carol McCabe, testified that Johns suffered from physical and mental disorders that gave him hallucinations, scattered thoughts and aggression. Johns'  mother drank heavily while pregnant, his family showed a history of mental illness, and other family members were allegedly abusive toward him, Williamson said.

“The descriptions of the violence in that household were disturbing,” Williamson said, citing Department of Social Services records that said Johns was physically and sexually abused. “Those are the influences Kevin was bathed in at the time he was learning to be a person.”

Johns likely suffers from schizo-affective disorder, which can include symptoms like seeing and hearing things that aren't there, and rapid mood swings from depression to manic energy,

Williamson said. When he wasn't treated with anti-psychotic medications, Johns stayed up all night talking to himself, or reported hearing voices telling him to do things.

Just days before he allegedly killed Parker, Johns met with  psychiatrist  Kristen Harris at the “Supermax” facility in Baltimore and reported hallucinations and impulses from some “evil force,” Williamson said.

“I like you, I don't want to hurt you, but I don't know what this thing can do outside this place,” Johns told her.

To reach his diagnosis, Williamson said he reviewed “thousands of pages” of other psychiatrists' reports and observations on Johns, who lived in institutions and foster homes from age 8 to 18, then

was left unmedicated with his family in Baltimore until his first murder arrest less than two years

later. He was not taking anti-psychotics when Parker was killed because doctors thought he was faking or “malingering” his symptoms.

Assistant Baltimore County State's Attorney Ann Bropst, who is prosecuting the death-penalty case after it was granted a change of venue to Harford, questioned how Williamson reached such a different conclusion than other psychiatrists, some of whom believed Johns was faking or exaggerating his symptoms for placement in a better prison.

Williamson said Johns' symptoms predated his time in prison and were not likely to have been faked then.

The trial before Judge Plitt is scheduled to continue Wednesday. If Plitt finds Johns guilty and criminally responsible for Parker's murder, Johns will get to choose again between a judge a jury to decide his sentence. The state is seeking the death penalty.

msantoni@baltimoreexaminer.com