My top 10 and the actual crimes they were inspired by with (Year of release-Country of making-Running time):
10-Lonely Hearts (2006-U.S.-1:48) The slayings by Raymond Fernandez and Martha Beck
9-In Cold Blood (1967-U.S.-2:13) A grayscale rendition of the Clutter Family massacre
8-Murderous Maids [Les Blessures Assassines] (2000-Fr.-1:34) The killings by the Papin Sisters
7-Let Him Have It (1991-U.K.-1:55) The controversial Bentley and Craig Case
6-Borderland (2007-U.S.-1:45) The cult murders at Matamoros
5-The Man From the Pru (1989-U.K.-1:30) The unsolved murder of Julia Wallace
4-True Confessions (1981-U.S.-1:50) A film inspired by the unsolved Black Dahlia murder
3-10 Rillington Place (1971-U.K.-1:51) The crimes of serial killer John Christie
2-The Young Poisoner's Handbook (1994-U.K.-1:39) The serial murders of Graham Young
1-White Mischief (1988-U.K.-1:48) The unsolved murder of Lord Errol