A man recently released from the prison is a suspect in the murder of his own wife. The woman's lover, a journalist, asks his partner for help to find proof of Michel's innocence and that the incident does not turn into a scandal.
A psychotic man opens fire in a diner, murdering numerous people before killing himself. The survivors struggle in different ways following this horrendous event: a doctor doubts his own instincts and elects to use an experimental medical procedure on his wife, while a gambler believes he's on a lucky streak. A waitress begins engaging in promiscuous sex, and a young girl whose father is among the dead gains unexpected fame.
Set in a gritty and decadent 1970s America, American Boogeyman follows the elusive and charming killer and the manhunt that brought him to justice involving the detective and the FBI rookie who coined the phrase ‘serial killer’.
Megan Carter is a reporter duped into running an untrue story on Michael Gallagher, a suspected racketeer. He has an alibi for the time his crime was allegedly committed—but it involves an innocent party. When he tells Carter the truth and the newspaper runs it, tragedy follows, forcing Carter to face up to the responsibilities of her job when she is confronted by Gallagher.
In the middle of the night, deputy Philippe Dubaye wakes up his old friend Xavier Maréchal with disturbing news: he has just killed Serrano, a racketeer with extant political connections. Serrano kept proofs of Dubaye's involvement in corrupt dealings and was poised to use them against the deputy. Xavier readily agrees to cover up for his old pal Philippe, but he soon runs into difficulties. Nobody believes Dubaye's alibi. And everybody -- influential personalities, powerful businessmen, dubious go-betweens and the police -- wants to get hold of the documents that served to blackmail Dubaye; by all possible means...
Industrialist Pierre Verdier kills his mistress Jeanne Ancelin by throwing her off a train. Her husband, Ancelin, decides to take revenge on his wife's murderer, who has been acquitted by justice.