Texas student pleads insanity in stabbing death of piano professor

A college student who claimed he stabbed and slashed his piano professor more than 200 times because he thought she was a robot intent on killing him pleaded not guilty by reason of insanity to murder Tuesday.

Jackson Ngai, 24, went on trial for attacking University of Texas professor Danielle Martin with a meat cleaver, scissors and other sharp items in her kitchen in 2004.

Ngai's attorney has said Ngai believed Martin was a robot or was controlled by a computer chip in her brain and was trying to kill him. On her body was a handwritten note that said, "Computer chip in brain."

Prosecutors acknowledged Ngai's history of mental illness but said they will prove he knew right from wrong when Martin was killed.

If a jury decides Ngai was insane, a judge could send him to a mental institution for the rest of his life. He could get life in prison if convicted of murder.

Ngai had checked out of a mental health treatment center less than a day before Martin was killed, AP reported. V.A.