The Metro Police Department is the local law enforcement for the city of Fairport. It is presumed that FPD has all the assets that many metropolitan police departments have, such as Riot Control and other relevant divisions necessary for their intervention during the events of F.E.A.R.
From the numerous news radio reports in F.E.A.R., it is known that the FPD blocked off and evacuated the South River Wastewater Treatment Plant, the Armacham Technology Corporation Headquarters and the Auburn District during the uprising of Paxton Fettel. As the crisis worsened, they began to evacuate the entire city, up until an explosion in the Auburn District leveled the city. How many of their number survived the explosion and the resulting war with Armacham Technology Corporation Forces is unknown.
It is important to note that it is unknown if they at any time engaged in combat with Replica Forces in or around the Quarantine Zone. If they did engage the Replica Forces, the equipment and weapons they had were most likely police-issue weapons and armor, so any fight between Replica Forces and law enforcement would have been decidedly one-sided.
Some of their abandoned vehicles do appear relatively in one piece as black-and-white cruisers with standard light bars. How many and if any of the force remains is unknown, however, their lack of presence in F.E.A.R. 2 suggests that most of them may have been killed by the Origin Facility Explosion, ATC soldiers and Replicas. If any units survived the blast, they may be helping the National Guard evacuate the remaining populace.
In F.E.A.R. 3, the Metro Police force is seen to have been decimated. The only trace of them in the game is a few scattered police barricades and FPD vehicles set up at check points meant to evacuate the city and treat the wounded. With ATC security forces under orders to cover everything up, and many citizens having been driven to insanity by the psychic rage of Alma Wade, the Metro Police were probably wiped out under overwhelming forces. It is also possible that many of their officers fled the city after the explosion.