The schizophrenic killer of a Manhattan psychotherapist is being retried in a meat cleaver attack that turned an office into a bloodbath.

Opening statements began Monday in David Tarloff's murder trial. It's prosecutors' third attempt to convict him in Kathryn Faughey's 2008 death.

Tarloff admits he killed Faughey while aiming to rob her colleague. Tarloff's defense argues he was too psychotic to be held criminally responsible.

But Manhattan Assistant District Attorney Evan Krutoy told jurors Monday that Tarloff "knew exactly what he was doing."

Tarloff has said he was seeking money to get his mother out of a nursing home.

A trial last year ended in a hung jury. A 2010 trial attempt foundered during jury selection because Tarloff's behavior disintegrated and he was found unfit for court.