A veteran Baltimore police detective died in the hospital today, one day after he was shot in the head by an unknown gunman, police said.

Homicide detective Sean Suiter, an 18-year veteran with the Baltimore Police, was conducting a follow-up to a homicide investigation around 5 p.m. Wednesday when he saw a man engaging in suspicious activity, police said.

Suiter approached the man and was shot in the head shortly after, police said.

The officer’s partner was nearby and rushed over to render aid, they added.

The officer was immediately taken to the hospital and placed on life support, a hospital official said.

Suiter was in “very, very grave condition” Wednesday evening and was fighting “for his life,” Baltimore Police Commissioner Kevin Davis said.

Suiter, 43, died around noon today, authorities said.

He was a married father of five.

Davis said today that Suiter was “a loved guy” who “loved being a cop.”