Published: Jan 15, 2014 11:49 AM EST
Updated: Jan 15, 2014 7:38 PM EST

LEE COUNTY, Fla.- A Psychiatrist testifying in the murder trial of Andrew Castor says Castor didn't know right from wrong when he stabbed a woman to death in her Cape Coral apartment in 2008.

Castor's lawyers have said from the start that he was insane at the time of the murder. They intended to prove that to the jury Wednesday afternoon by putting their key witness on the stand.

The defense hired Dr. Michael Maher to evaluate Castor's state of mind more than two years after the stabbing. He says Castor has a history of severe depression and mental illness and was abused as a child. The depression escalated into his adult life and made his disassociated.

Dr. Maher says Castor didn't have an understanding of what he was doing when he killed his neighbor Bianca Interiano on August 2, 2008. "He realized there was a horrifying, not his word my word, amount of blood on his hands when he got back to his apartment" says Dr. Maher.

"He remembered a state of mind, a feeling of being overwhelmed by rage and hate." Dr. Maher goes on to say, "and in some way a feeling of hostility directed at him, but mostly rage and hate."

Cape Coral police say Castor stabbed Interiano multiple times with one of his knives.

Before the state rested Wednesday morning, prosecutors had a forensic technologist testify about DNA found on the knife and underneath Interiano's fingernails.

On Thursday, proseuctors will call a rebuttal witness. The case could go to jurors Thursday afternoon.

Castor faces life in prison if convicted.