A 29-year-old woman was stabbed to death in front of her Manhattan home early Monday — and investigators are eyeing her ex-boyfriend in the murder, cops and law enforcement sources said. 

A man wearing all black knifed the victim, identified as Shirley Rodriguez, multiple times in the head, neck and shoulder outside her apartment building on Haven Avenue, near West 175th Street, in Washington Heights around 5:30 a.m., authorities and sources said. 

The killer then ran off, into nearby Fort Washington Park, cops said.

The suspect is a 33-year-old man believed to be the victim’s ex, according to the sources, who noted police were probing the brutal attack as a domestic crime.

Rodriguez was unconscious when first responders arrived. She was rushed to Harlem Hospital, but could not be saved.

No arrests had been made by later in the morning.