UPPER WEST SIDE, Manhattan (WABC) -- A father of two fatally stabbed his family and then took his own life in their Upper West Side apartment, the New York City Medical Examiner determined.
Detectives believe Edison Lopez, 41, stabbed his wife, two young sons and then himself.
The murder-suicide occurred in the family's apartment on Monday where Lopez worked as a superintendent.
The bodies of 3-year-old Lucien, 1-year-old Calvin, and 40-year-old Alexandra were found in a common area of their apartment with numerous stab wounds.
Edison Lopez was found on the bed with one stab wound to his neck.
A kitchen knife was found next to him within arm's reach. Two more kitchen knives were found next to the other three.
The bodies were discovered by the victim's father and the father's brother, who hadn't heard from the family since 10 a.m. the day before.
The grandfather, also a superintendent, unscrewed the peephole on the door from the outside, looked in and was horrified to see his daughter-in-law's motionless body on the floor. That's when he called 911.
No one had seen the family since the morning before, when they had a play date at the Intrepid with another couple that had two children the same age.
Relatives and neighbors described the family to detectives as very stable and loving, with no signs of any issues.
"I think it's crazy. I think it's scary," resident Jeff Kimmel said. "I couldn't imagine, when this happened and we were all shaking, the first thing we thought is who could have come into our building and do this?"
Neighbor Philip Caggiano told Eyewitness News that he knew the 41-year-old dad when he was just a baby.
"I thought how great to live on this street with this happy family," he said. "This is heartbreaking, just heartbreaking."
Authorities say before Monday, there were no 911 calls related to the family and no domestic violence history.
Authorities also say the father was apparently leaving his position as superintendent of the building for a similar job in Hastings-on-Hudson in Weschester County.
The family had to vacate their apartment on the Upper West Side by September 1, but their new place was not ready for them to move in yet.
Detectives are looking into stress from the timing of the move as a possible motive.
Based on current evidence recovered at the scene, the killing occurred less than 24 hours before the bodies were found at 2:55 p.m. Monday.
The investigation remains ongoing.