A 49-year-old man is in critical but stable condition after he was shot in the back inside his apartment building in Claremont.

Detectives say two men got into an argument inside the building on West Farms Road. They say the shooter went into his room and returned to a common area of an apartment with a gun.

The victim was shot in the back, chest and head.

It’s not yet clear why the men were arguing. Police say the two men knew each other and lived in the same building.

Neighbors say the victim was a janitorial staff member of the building. 

The shooter has not yet been apprehended. Authorities are urging anyone with information to call Crime Stoppers at 1-800-577-TIPS.