The Rockland County District Attorney's Office has taken over the investigation into a fatal police shooting that left one man dead on Christmas Eve.

Police say the victim?s girlfriend called 911 from their New Hempstead home, claiming 41-year-old Thomas Jackson barricaded himself in the bathroom and threatened to commit suicide.

According to police, Jackson was emotionally unstable, and they had been his house before. This time, police say the incident escalated when Jackson allegedly approached the two responding officers with a switchblade, prompting one of them to open fire.

"The incident at hand involves a shooting in which a police officer feared for his life, and he took the action he felt he needed to take," says Detective Lt. Brad Weidel, of the Ramapo Police Department.

The officers involved in the incident were not injured, but they were taken to the hospital for a post-traumatic stress evaluation.

Ramapo Town Supervisor Christopher St. Lawrence reviewed the 911 tapes related to the incident and says he has no doubt the officer followed proper protocol.

In a statement released via e-mail, Rockland County District Attorney Thomas Zugibe said his office will conduct a "comprehensive grand jury investigation into the facts and circumstances."