A man fatally stabbed his girlfriend then jumped out the window of his Bronx apartment to his death Thursday, according to police.

Authorities said 26-year-old Lander Jones slashed 18-year-old Mabelyn Ariola's throat and stabbed her repeatedly in the back in his apartment at 325 E. 176th St. Jones then sliced his own wrist and jumped out the fifth-floor window to his death, officials confirmed.

Police recovered a knife inside Ariola's apartment, which was also in the same building.

The building superintendent spent Thursday morning hosing blood off the sidewalk where Jones landed. Jones' uncle said the man's relationship with Ariola was unhealthy.

"She had him locked up before, but she hurt him too," said Daniel Covington. "[She] stabbed him. We went to court about it."

Covington said he wants to reach out to Ariola's family as they also grieve. Jones' family plans to keep his memory alive by setting up a charity intended to stop violence among young people.

Police have said they do not know what prompted the deadly incident.

AP wire reports contributed to this story.