Americop is a vigilante from Marvel comics who would come into conflict with Captain America and later the Thunderbolts, while he sees himself as being on the side of "good" he employs tactics very similar to those of Punisher and as such is seen as a dangerous killer to other superheroes and villains alike. Like the Americops organization that would take up his name many years later the character was designed as an insight / protest into well-known police corruption, especially in the United States, albeit greatly dramatized for the setting (since superhero fiction is largely melodrama by design).
Americop was originally a police officer by the name of Bartholomew Gallows who grew increasingly disillusioned with what he saw as an inability by traditional law enforcement to protect society from criminals.
Thus he donned a vigilante persona by the name of Americop and went on a one-man crusade against crime, utilizing brutal tactics that were at odds not just with traditional law enforcement but the superhero community in general, turning him into a menace despite his apparently noble goals : he was rather undeterred by this and saw himself as "America's top law enforcer".
Due to his violent ways, Americop would end up getting into a confrontation with Captain America, who was appalled and shocked by the vigilante's brutality when the pair crossed paths hunting down a crime-lord known as Damon Dran, during this conflict Americop brutally murdered many of Dran's men but fled the scene before either Dran's remaining forces or Captain America could bring him down.
After the events of Civil War, S.H.I.E.L.D. considered recruiting Americop as part of their Initiative plan but was ultimately targeted by the Thunderbolts as a plan by Norman Osborn to have the vigilante kill off Bullseye and Penance.
Despite a fierce battle, Americop was downed by Penance and taken to the Thunderbolts HQ, presumed to be paralyzed but later died from his injuries.
Americop is not a superhuman being but as a trained law-enforcer was skilled in both firearms and unarmed combat, he also wore an suit of body-armor that heightened his strength and durability to superhuman levels.
Lastly he was prone to driving a large bullet-proof truck.