The Army vet who emerged as the No. 1 suspect in a vicious fatal stabbing outside the main post office is believed to have committed suicide in his girlfriend’s Philadelphia apartment, The Post has learned.
NYPD detectives late last night headed to Philly to confirm that Sirmone McCaulla — an ex-GI suspected in the Sunday slaying of 20-year-old Christopher Gutierrez — killed himself at 6 p.m. in the Pine Street residence, a law-enforcement source said.
McCaulla was reportedly found in a bathtub hugging a cable box and wearing a bag over his head.
As Philadelphia cops were investigating the suicide, NYPD detectives — also zeroing in on the gal pal in their manhunt for 28-year-old McCaulla — called them and determined the suicide victim was most likely the suspect, the source said.
Earlier yesterday, authorities said they had begun to focus on McCaulla after a cop who served with him in the Army recognized him from photos taken outside the James A. Farley Post Office slaying scene.
Surveillance cameras captured the bloody slaying and the moments before it, which Commissioner Ray Kelly described as a simple street altercation that turned deadly.
“[The killer] is walking north and the victim is walking south. It looks like they bump shoulders and they walk past each other, I would say 10 or 12 feet. They turn around and words are exchanged,” Kelly said.
“The victim takes his coat off as if they are going to have a fist fight and assumes a stance like a fighter.”
As the killer approaches, “he has something down at his side which turns out to be a knife,” and then “lunges and makes four quick strokes or jabs into the vic tim,” Kelly said.
Gutierrez collapsed on the steps of the post office and was later declared dead.
Images from the video, cou pled with published photographs taken by a German tourist, led several tipsters to call in, but the best clue came from the cop who recognized McCaulla from their time together in the Middle East.
Army officials were unable to provide detailed information on McCaulla’s service. In late 2008, he passed the FDNY exam and is on the waiting list. He worked as a FedEx deliveryman in The Bronx as recently as April, but was fired for allegedly stealing packages, according to court records. McCaulla had two other arrests, for robbery and assault.
Additional reporting by Murray Weiss