Best Investigation movies of 1970s

Actors : John Hurt, Veronica Cartwright, Sigourney Weaver, Tom Skerritt,
Directors : Ridley Scott,

After a space merchant vessel perceives an unknown transmission as a distress call, its landing on the source moon finds one of the crew attacked by a mysterious life-form, and they soon realize that its life cycle has merely begun.

Actors : Graham Chapman, Eric Idle, Terry Gilliam, John Cleese,

King Arthur and his knights embark on a low-budget search for the Grail, encountering many, very silly obstacles.

Actors : Perry Lopez, Faye Dunaway, Jack Nicholson, John Huston,
Directors : Roman Polanski,

A private detective hired to expose an adulterer finds himself caught up in a web of deceit, corruption, and murder.

Actors : Sissy Spacek, Ramon Bieri, Martin Sheen, Warren Oates,
Directors : Terrence Malick,

An impressionable teenage girl from a dead-end town and her older greaser boyfriend embark on a killing spree in the South Dakota badlands.

Actors : Al Pacino, John Randolph, Jack Kehoe, Biff McGuire,
Directors : Sidney Lumet,

An honest New York cop named Frank Serpico blows the whistle on rampant corruption in the force only to have his comrades turn against him.

Actors : Sean Connery, Lana Wood, Jill St. John, Charles Gray,
Directors : Guy Hamilton,

A diamond smuggling investigation leads James Bond to Las Vegas, where he uncovers an evil plot involving a rich business tycoon.

Actors : Roger Moore, Barbara Bach, Curd Jürgens, Richard Kiel,
Directors : Lewis Gilbert,

James Bond investigates the hijacking of British and Russian submarines carrying nuclear warheads, with the help of a K.G.B. Agent, whose lover he killed.

Actors : Roger Moore, Clifton James, Jane Seymour, Yaphet Kotto,
Directors : Guy Hamilton,

007 is sent to stop a diabolically brilliant heroin magnate armed with a complex organization and a reliable psychic tarot card reader.

Actors : Michel Auclair, Alan Badel, Terence Alexander, Edward Fox,
Directors : Fred Zinnemann,

A professional assassin codenamed "Jackal" plots to kill Charles de Gaulle, the President of France.

Actors : Reggie Bannister, A. Michael Baldwin, Bill Thornbury, Kathy Lester,
Directors : Don Coscarelli,

A teenage boy and his friends face off against a mysterious grave robber known only as the Tall Man, who keeps a lethal arsenal of terrible weapons with him.

Actors : Adrienne Barbeau, John Houseman, Jamie Lee Curtis, Janet Leigh,
Directors : John Carpenter,

Legend says that Antonio Bay was built in 1880 with blood money obtained from shipwrecked lepers, which no one believes. On the eve of the town's centennial, many plan to attend the celebrations, including the murdered lepers.

Actors : Arthur Hill, David Wayne, James Olson, Kate Reid,
Directors : Robert Wise,

A group of scientists investigate a deadly new alien virus before it can spread.

Actors : Harvey Korman, Mel Brooks, Madeline Kahn, Cloris Leachman,
Directors : Mel Brooks,

Mel Brooks' parody of Alfred Hitchcock films.

Actors : David Gulpilil, Richard Chamberlain, Frederick Parslow, Olivia Hamnett,
Directors : Peter Weir,

A Sydney lawyer defends five Aborigines in a ritualized taboo murder and in the process learns disturbing things about himself and premonitions.

Actors : Roger Moore, Michael Lonsdale, Richard Kiel, Lois Chiles,
Directors : Lewis Gilbert,

James Bond investigates the mid-air theft of a space shuttle, and discovers a plot to commit global genocide.

Actors : Gregory Peck, David Warner, Harvey Stephens, Lee Remick,
Directors : Richard Donner,

Mysterious deaths surround an American ambassador. Could the child that he is raising actually be the Antichrist? The Devil's own son?

Actors : Britt Ekland, Edward Woodward, Christopher Lee, Diane Cilento,
Directors : Robin Hardy,

A police sergeant is sent to a Scottish island village in search of a missing girl whom the townsfolk claim never existed. Stranger still are the rites that take place there.

Actors : Orazio Orlando, Gianni Santuccio, Florinda Bolkan, Gian Maria Volontè,
Directors : Elio Petri,

A chief of detectives, homicide section, kills his mistress and deliberately leaves clues to prove his own responsibility for the crime.

Actors : Edward G. Robinson, Leigh Taylor-Young, Charlton Heston, Chuck Connors,
Directors : Richard Fleischer,

In the world ravaged by the greenhouse effect and overpopulation, an NYPD detective investigates the murder of a big company CEO.

Actors : Jon Finch, Barbara Leigh-Hunt, Anna Massey, Barry Foster,
Directors : Alfred Hitchcock,

A serial murderer is strangling women with a necktie. The London police have a suspect, but he is the wrong man.