This guy is perhaps our most prolific killer, with about 1,000 murders to his name. Back in '01, he went on a 2-night killing spree, which resulted in the deaths of numerous members of the Punchinello crime family and a number of employees working for Aesir Corporations. His second spree in '03 lasted another 2 nights, and the overwhelming majority of his victims were hired hitmen who worked for the Russian Mafia.
"Max Payne", as they call him, real name Nick Kelly, was initially hunted by the NYPD for the murder of DEA Agent Alex Balder, but it was later discovered that Kelly did not kill Balder. As a result of the huge number of his victims having criminal records, Kelly was set free. However, in 2003, he went through the same scenario, though one of his victims was an officer of the NYPD, who was later found out to be working with the Mafia. Payne was subsequently kicked off the force. The most damning thing? He wasn't thrown in jail for it. Despite the high casualty number, Kelly has been debated on for years, and a large number of people say that he provided a public service by acting like Chuck Bronson.
(A lot of this involved some creative writing, and I haven't played the 3rd game yet.)