Police have lined up four rows deep to pay respects to a fellow officer who was among the victims of a gunman's rampage at a Manhattan office tower.

The horrific mass shooting at a Midtown office building on Monday was the deadliest gun attack in the Big Apple in 25 years. Shane Tamura gunned down four innocent people — including an NYPD cop and a business executive — before turning the gun on himself late Monday.

Services begin with a viewing at a Bronx mosque for NYPD officer Didarul Islam followed by a procession. Officer Islam was off duty and working a security job when he was shot and killed by a gunman in a Midtown Manhattan office building.