(Reuters) - The man suspected of killing an off-duty Louisiana police officer was taken to a an area hospital after he shot himself on Friday evening, bringing to a close an hours-long standoff, authorities said.

The suspect, identified as 32-year-old Sylvester Holt, had been in a standoff with police and crisis negotiators for hours on New Orleans' Crescent City Connection bridge when he shot himself, Louisiana State Police Trooper Melissa Matey said.

Matey said Holt's condition was not known.

Westwego Police Officer Michael Louviere, 26, was heading home shortly after 6 a.m. local time on Friday when he stopped to respond to an apparent accident outside New Orleans. He exited his marked vehicle to offer aid, Jefferson Parish Sheriff's Office spokesman Colonel John Fortunato said.

"The suspect comes up from behind and shoots him in the back of the head," Fortunato said, calling the shooting "a cold-blooded killing."

Fortunato said Louviere was wearing a police uniform, but did not appear to be targeted as a law enforcement officer. A woman was also killed in connection to the crime, authorities said.

(Reporting by Letitia Stein in Tampa, Fla. and Curtis Skinner in San Francisco; Editing by Tom Brown and Diane Craft)