A 14-year-old Bronx boy was arrested for the Thursday murder of his friend, cops and sources said.

Patrick Mahoney was charged Friday with murder, manslaughter and criminal possession of a weapon in connection of the fatal shooting of Jacob Borbin, also 14, according to sources and court officials.

Investigators were looking into the possibility that the teens were playing with a .380 caliber handgun in the lobby of an apartment building at East 194th Street and Briggs Avenue in Fordham Manor.

Borbin was allegedly shot in the chest when the gun went off. He was pronounced dead at St. Barnabas Hospital, according to cops.

Mahoney was remanded after his Saturday evening arraignment and was set to appear in felony youth court Monday.