LAS VEGAS – Robert A. Maheu, a former Howard Hughes confidant and CIA operative once involved in a failed plot to poison Fidel Castro, has died in a Las Vegas hospital. He was 90.

Maheu was born in Waterville, Maine.

He died Aug. 4 of congestive heart failure at Desert Springs Hospital, according to his son, Peter Maheu.

Maheu was the public face of Hughes’ massive corporate empire in the 1960s, a period in which the troubled aviator and one-time Hollywood playboy was increasingly reclusive and dogged by phobias. Hughes spent the later part of the decade holed up in his Las Vegas hotel suite, directing Maheu and his casino and development interests through memos.

Maheu said he occasionally protected the billionaire from himself.

“There were some memos where references pertaining to absolute power were sent to me. To protect him from himself, I took no action on those memos,” Maheu told The Associated Press in a 1986 interview. “To buy a particular president or to buy someone into the White House – no action was taken in that direction.”

Maheu was an expert in discretion.

He worked for the FBI in the early 1950s and later as a private investigator who counted the CIA among his clients.

In 1960, Maheu was enlisted by the CIA to recruit a mobster for a “sensitive mission requiring gangster-type action,” according to a recently released CIA dossier known as “the family jewels.”

“Fidel Castro is the mission target,” the document said.

Maheu approached reputed gangster Johnny Roselli and represented himself as an agent for international corporations wanting the Cuban leader dead, according to the document.

Roselli introduced Maheu to two wanted mobsters, Momo Giancana, Al Capone’s successor in Chicago, and Santos Trafficante. The CIA gave them six poison pills, and they tried unsuccessfully for several months to have several people put them in Castro’s food.

The plot was dropped after the failed CIA-sponsored Bay of Pigs invasion of Cuba, the document said.

Maheu later described his role in the Cold War plot in stark terms.

“War will make you do certain things,” he told the Las Vegas Review-Journal in 1997.

“He said it took him many nights to decide to work for the CIA,” Peter Maheu said. “But for the greater good of the country, he agreed to go ahead. It was a very patriotic thing in his mind. Even though it conflicted with his Catholicism.”

Peter Maheu described his father as devout, energetic and loyal.

He returned to investigative work after he was abruptly fired by Hughes’ company shortly after its chief mysteriously slipped out of Las Vegas in 1970. Maheu sued for breach of contract and won a $2 million judgment.

“He always had a respect for Howard Hughes,” Peter Maheu said. “But he felt that he was betrayed by the people around him.”

“The biggest regret of my life is not grabbing Howard Hughes with my two hands, shaking him by the shoulders and saying, ‘Enough is enough,”‘ Robert Maheu told the Review-Journal.

After leaving Las Vegas, Hughes traveled the globe. His legal problems increased and his health deteriorated. He died in 1976.

Maheu remained in Las Vegas, a city he adored.

“He called it a city with a heartbeat,” his son said.

He is survived by his three sons and 10 grandchildren. Services are scheduled Aug. 9.