FAQ

Colt's Python in .357 magnum with 4" barrel and "Royal Blue" finish.

This line caused great controversy amongst gun enthusiasts as it suggested that Dirty Harry used the much weaker 44 Special cartridge in his revolver rather than the tremmendously powerful 44 Magnum (the Smith and Wesson Model 29 capable of using both). According to screenwriter John Milius the crew simply fluffed his dialogue, what Harry means is that he uses a specially prepared slightly lighter version of one of the strongest varieties of 44 Magnum bullets in order to give him 'less recoil and more control'.

There are five: (1) Dirty Harry (1971), (2) Magnum Force (1973), (3) The Enforcer (1976), (4) Sudden Impact (1983), and (5) The Dead Pool (1988).

The most likely answer is that the cab driver supplied a description of the pimp to the police. Perhaps he was interviewed by a sketch artist as well. They probably were able to identify the pimp through both a mugshot and through a background check on the victim. Once there, it was a matter of one of the killer cops tracking down the car. It's also possible that the killer had already targeted the pimp for previous crimes or simply for the fact he was obviously a pimp. It was only coincidence that he was killed the day after murdering his prostitute.