A research scientist hires old friend Cannon when her husband begins to display erratic behavior after joining a top-secret Army project.
An angry father is determined to prove his son's death in a plunge from the cliffs of Acapulco was not a suicide.
A revenge-seeking father sets out after his slain daughter's pro football quarterback boyfriend despite the solidity of the man's alibi.
Cannon is hired by a racketeer (Robert Loggia) to capture the hired killer responsible for an attempt on the life of the gangster's wife.
Cannon investigates possible extraterrestrial involvement in the death of an internationally known space scientist.
A multimillionaire hires Cannon to avoid police involvement in the possibly fraudulent kidnapping of his grandson.
Cannon's military past in Korea returns to haunt him when he becomes the target of a South Korean officer's revenge.
The disappearance of an accountant coincides with a huge fraud investigation set to begin against his employer, a land-development firm.
Despite hints of a frame-up, a crusading newspaper editor is arrested after being found unconscious with a murdered girl in a hotel room.
A boy is initially disbelieved when he claims two men dressed as Arabs shot at him while they wheeled a patient into a makeshift hospital.
A former film actress hires Cannon to find her son, who disappeared just after returning from three years of traveling.
The son (Carl Franklin) of a slain black political leader hires Cannon to look into the possibility of a conspiracy.
A retired general's (Morgan Woodward) son (Dean Stockwell) becomes a hero to his father after being accused of killing a terrorist leader.
A policewoman comes to Cannon for help when her superiors won't let her hunt the men who assaulted her.
An heiress's boyfriend receives a death threat from the Chinese underworld in the form of a melting snowman with a hatchet in its head.
A petroleum company's vice-president, on the verge of being fired after being accused of misappropriation of funds, asks Cannon for help.
Cannon goes to retrieve the body of a friend's son killed in a freak sea accident.
Terrorists give Cannon poison that will kill in 72 hours without an antidote, which they will exchange for a defector.
Cannon and his old police partner (Leslie Nielsen) are asked by their ex-superior to reopen the probe of a corrupt officer thought dead.
A drugged, battered girl insists her friend (Donna Mills), a singer, is being held prisoner in the Hollywood hills.
A reopened murder case involves a former Green Beret and a convict who surprisingly rejects parole.
Cannon looks into charges against a physician (David Birney) in the death of a woman he was treating who was in an apparent diabetic coma.
Despite heavy evidence against him, Cannon takes on the case of a deliveryman charged with murder.
Cannon hears the confession of a hit man who admits to killing the detective's wife and baby son 14 years before.
Cannon uncovers a crime while searching for a teenage runaway.
Cannon has a 24-hour deadline to rescue a wealthy industrialist's daughter after she is taken by a terrorist group.
An ex-convict (Clu Gulager) attempts suicide to force Cannon to search for the fake CIA agent who sent him to jail.
A disenchanted wife planning to leave her husband flees to a sanitarium she once inhabited after seeing her lover commit a murder.
A Midwestern mayor calls in Cannon to clean up police corruption in his community that has resulted in a string of warehouse burglaries.
Cannon suspects he has a double after two nearly successful attempts on his life follow a strange woman's greeting to him at the airport.
A former convict boards an Atlanta airliner for a reunion with his daughter but is missing when the plane lands.
Cannon encounters corruption when he investigates the attempted assassination of a state assemblyman.
Cannon is framed when the supposed pursuer of the girl he was hired to protect is found murdered.
A lawyer (Gary Lockwood) returns to the scene of his college football triumphs to escape a crime mob pursuing him.
A tape recording detailing the murder of a girl reported missing brings Cannon to a rural town to solve the crime.
Cannon becomes the target of a setup when he fakes the murder of a mobster to allow the man to testify against the mob as part of a deal.
Cannon goes under cover as a hired killer to uncover the dark secret behind the blackmail of a former Army captain.
A chess champion and financial wizard suddenly breaks off his engagement, leading his puzzled fiancee to ask Cannon to find the reason.
Cannon finds himself involved in an assassination attempt and the manhunt for an alleged World War II criminal.
A falsely accused suspect faces injury at the hands of a mob unless a rapist/murderer's mother reveals vital evidence.
Cannon feels victimized when he discovers the true identity of the insurance man who hired him to look into a girl's auto-accident death.
An ex-police officer (Dane Clark) intends to avenge his brother who died while doing a favor for Cannon.
Cannon becomes involved in a terrorist's vendetta through his friendship with the intended victim, an ex-colleague.
A domineering tycoon whose daughter has been missing for a long time tries to force Cannon to search for the girl.
The woman Cannon was hired to guard eludes him at the airport, only to turn up later robbed and slain.
An unofficial probe conducted by Cannon's friend (Ford Rainey), a retired police officer, makes both him and Cannon targets for hit men.
To save a Catholic bishop (Richard Kiley), Cannon must pose as a hired assassin and infiltrate a crime mob.
A retired call girl (Stefanie Powers) resists cooperating when Cannon asks her to be the lure in a police plan to trap her former boss.
An escaped mental patient bent on vengeance stalks Cannon during the investigator's vacation at a mountain lake.
An English heiress (Dana Wynter) suspects the supposedly suicidal death of her father on a Caribbean island was in reality a homicide.
A naive schoolteacher hires Cannon to investigate the murder of her love interest, a smooth-talking dance teacher at a lonely-hearts club.
Cannon moves among evangelists and carnival performers while probing the disappearance of a faith healer's protege.
The widow of a big-game hunter believes her husband was murdered, despite evidence suggesting he was mauled to death by an ailing lion.
A flamboyant attorney (Peter Haskell) defends a doctor (Perry King) charged in the death of a financier during an apparent jail escape.
A shy heiress hires Cannon to stop attacks of vandalism she claims are the handiwork of her long-missing sister.
On a mission to deliver ransom money, Cannon falls prey to opportunists while wandering in the desert with amnesia.
Cannon becomes the target of a sniper when a mercenary (Jack Cassidy) hires the detective for a murder investigation.
A boxing contender's (Nick Nolte) fiancee asks Cannon's help when the fighter threatens to leave the country just before a major bout.
Cannon finds a clue to a bizarre harassment case in the involvement of a pilot (Robert Goulet) in a $1 million hijacking years before.
Cannon contacts the legal counsel (Leslie Nielsen) for an American Indian organization when he tries to clear an Indian of murder charges.
A socialite (Dina Merrill) is astonished to discover that her missing fiance is actually a married man being sought by his Swiss wife.
A judge's (Simon Scott) daughter (Kelly Miles) disappears while her father is presiding over a case involving a major syndicate kingpin.
Cannon's longtime friend (Jason Evers), a police detective, is suspended after the escape of the top suspect in a counterfeit-stock ring.
Cannon enters the circle of admirers around a lovely model when he tries to clear the man charged with her murder.
Cannon's prime suspect in a $50,000 payroll burglary at an electronics plant turns out to have been in jail when the crime was committed.
Cannon is hired to track down an escaped convict who may have been framed for murder.
Cannon investigates the unexplained disappearance of an airplane carrying $3 million in securities.
An innocent publicist (Anne Francis) finds herself charged with a producer's murder when she becomes involved in a complicated conspiracy.
Cannon is accused in the slaying of a mobster's girlfriend who contacted him in hope of getting government immunity for her lover.
Killer dogs slay two survivors of an Army unit whose commanding lieutenant became paralyzed in a deliberate attack.
A lawyer (Martin Sheen) presents Cannon with a will provision requiring the detective to look into the death of the lawyer's late client.
Cannon faces a small cattle town's hostility when he tries to clear a friend of two homicide charges.
A wealthy arts patron (Beverly Garland) hires Cannon to find her long-missing stepson.
A news reporter (Marlyn Mason) asks old friend Cannon to help her when she faces a contempt charge for refusing to reveal a news source.
An admitted mass murderer (Anthony Zerbe) hires Cannon and tells the investigator to prevent him from killing again.
A rural newspaper editor (Barry Nelson) hires Cannon to find evidence linking a powerful local community leader to a series of murders.
An importer's ex-wife (Geraldine Brooks) hires Cannon when her son is reportedly jailed on a drug charge in Turkey.
Cannon searches for a missing lawyer and exposes the murderer of a police officer.
Cannon tries to prevent the violent revenge sought by a high-school teacher whose daughter died at a jet-set party.
A photographer (Susan Oliver) finds Cannon hesitant to search for her missing boyfriend after the detective learns his quarry's identity.
A suspect (Sondra Locke) is missing in Cannon's investigation of the death of a famed marine biologist.
An aspiring actress (Arlene Golonka) plays an important part in a plot to take over a vast real estate empire.
An amnesia victim (John Vernon) seems to be holding an important secret wanted by unknown assailants.
Cannon helps collar an underworld figure who is threatening the life of a gambler's wife.
Cannon's old friend (Andrew Duggan), a boat builder, finds himself charged in his son's hunting-accident death.
Frank Cannon is hired by an ex-policewoman whose husband is being blackmailed.
Cannon looks into the disappearance of a real-estate tycoon's body after the man's plunge from a precipice overlooking a development site.
Cannon leads the hunt for a missing rancher who has been taken hostage by a hostile narcotics smuggler.
Cannon accidentally uncovers a major hijacking operation.
Cannon tries to clear a black physician who has been framed in a drug-theft case.
Cannon aids a sheep rancher charged in the death of an illegal Mexican immigrant caught in a coyote trap.
A rival private investigator pressures Cannon in the matter of a drinking-establishment fire.
Cannon is hired to protect a lawyer (Jessica Walter) whose clients are unpopular with the public.
Cannon's search for a missing husband reveals plans for an upcoming, daring robbery.
Deaths resulting from a ski-lift tragedy bring Cannon to Colorado to investigate.
Cannon tries to help a close friend accused of murdering his wife.
A young convict falls prey to a prison mastermind who is in charge of a vast gambling empire operating behind bars.
A wealthy manufacturer and gun collector whose younger brother has suddenly vanished hires Cannon to investigate.
A man accused of setting the fire that killed his estranged wife comes to Cannon for help in proving his innocence.
Mercenaries devise an unusual plan to aid in the overthrow of a small African country.
Frightened parents call in Cannon when their teenage daughter falls under the mystical spell of a cult leader.
The life of a safecracker trying to stay within the law is threatened if he fails to cooperate in a $1 million theft.
A harassment campaign is directed at a doctor (Vera Miles) engaged in a medical research project at a state prison.
While protecting the life of a winemaker, Cannon discovers that the man's son is an impostor.
Frank Cannon investigates the theft of valuable relics from a church in Mexico.
A disabled policeman seeks revenge on the hoodlum who's responsible for his injury.
A thief dupes Cannon into providing him with a plan to change his identity and escape the country.
A disgruntled accountant plans to protest the production of deadly nerve gas by stealing a canister of the substance.
Cannon's simple assignment as bodyguard to a broker's daughter and grandchildren suddenly turns complex.
A missing bicycle provides a vital clue in Cannon's investigation of a salesgirl's mysterious death.
An aged attorney stands in the way of Cannon's investigation into a missing-person case.
Frank Cannon is hired by a woman who believes her missing brother may have been murdered.
Cannon assists a police detective friend who is being framed on a murder charge.
The death of a private-investigator friend during a missing-persons case leads Cannon to join the probe.
The trail of suspects in an armored-car robbery leads Cannon to a hamlet where he receives an unfriendly greeting.
Cannon is called in when a gubernatorial candidate wants to avoid police involvement in rescuing his kidnapped son.
An insurance company hires Cannon to investigate the plane-crash death of a country-and-western singer.
A trucking company plagued by a series of hijackings hires Frank Cannon to investigate.
The death of a secretary prompts her employer, a middle-aged banker (William Windom), to hire Cannon to investigate.
An insurance company hires Cannon to find the men who robbed a rodeo of $100,000.
Private detective Frank Cannon investigates the murder of his ex-girlfriend's husband and gets entangled in small-town corruption.
Private detective Frank Cannon investigates the murder of his ex-girlfriend's husband and gets entangled in small-town corruption.