A man fatally shot his girlfriend inside their Bronx apartment building before turning the gun on himself early Friday, cops said. 

Kristina Jones, 41, was killed when her 42-year-old beau shot her in the neck in the fifth-floor hallway of their building on Williamsbridge Road in Allerton just after midnight, cops said.

He then shot himself in the head, police said. 

The man – whose name was not immediately released by cops – was pronounced dead at the scene, authorities said. 

A gun was found near his body, cops said. 

Jones was rushed to Jacobi Medical Center, where she too was pronounced dead, police said. 

The circumstances leading up to the murder-suicide were not immediately known.