Robert A. Maheu: Aide to Howard Hughes

Robert A. Maheu knew what power was. It was when you called the White House, and asked to see Lyndon Johnson. In fact, the President was trying to snatch a few days off at his Texas ranch, but still had a helicopter sent to ferry his unexpected guest from the nearest airport. He would give another example. "If you can pick up the telephone the night before the Academy Awards and say, 'By the way, I'm going to need another table for eight people tomorrow,' and they don't even burp – that's power."

At the summit of his career, this sort of thing was routine for Bob Maheu. Part of his success reflected his own gifts as a deal-maker and fixer. But the biggest reason was his role as "alter ego" to Howard Hughes: aviator, inventor, movie producer, tycoon and, for the last third of his life, paranoid recluse, who was long one of America's richest men.

For a decade or more – and above all for the four years he was Hughes' director of Las Vegas operations until his boss abruptly fired him in 1970 – Maheu was Hughes: his eyes, his ears, his voice to the world. Maheu represented the invisible billionaire in the boardroom, at dinners with the mighty of the day, in appearances before Congressional committees, in meetings with Presidents. That was precisely how Hughes wanted it. The two men talked on the phone, or communicated by handwritten memo, up to 20 times a day. But they never met.

Still physically imposing and compellingly fluent, Maheu described the extraordinary relationship in a filmed interview a few months before his death, "One day in 1958," he recalled, "I could have made three separate $150m decisions on behalf of a man with whom I'd never been in the same room. Yes, I saw him at a distance on two occasions, but I never eye-balled him, we never shook hands, we never talked face to face."

These moneyed, immensely powerful circles were far removed from Maheu's origins in a French-speaking family. A grocer's son who grew up in a poor town in Maine, 100 miles south of the Canadian border, after graduating from Holy Cross College in Massachusetts Maheu joined the war-time FBI, where he helped run a French double agent against the Nazis. By 1954 he had set up his own private investigation company, where he did undercover work for the CIA – "cut-out" jobs, he wrote in his 1992 autobiography Next to Hughes, "in which the agency could not officially be involved".

The most spectacular of them came in 1960 when the CIA enlisted Maheu and the Mafia kingpins Sam Giancana, Johnny Roselli and Santo Trafficante in a plot to poison Fidel Castro. The scheme was abandoned after the failure of the Bay of Pigs invasion in April 1961, but long afterwards Maheu still trembled at the memory: "If anything went wrong I was the fall guy, caught between protecting the government and protecting the mob, two armed camps that could crush me like a bug."

Years before, that, however he was doing work for Hughes. A first assignment went off perfectly, the second was a near-disaster. Hughes asked Maheu to arrange surveillance of the actress Ava Gardner, whom he was pursuing, to check on her meetings with Frank Sinatra. But the private eye Maheu hired botched the job utterly, and a posse of reporters was waiting when Sinatra and Gardner returned from a boat trip on Lake Tahoe.

Maheu assumed that the fiasco would be the end of their association. Not so. By 1966 he was working full-time for the tycoon, who had rented the top floor of the Desert Inn in Las Vegas for what was booked as a 10-day stay. But 10 days turned into 15, right in the Vegas high season, and because Hughes did not gamble, the hotel asked him and his entourage to leave.

Hughes asked Maheu for advice. "If you want a place to sleep, buy a hotel," came the reply. Thus did Hughes acquire the Desert Inn, for $13m. Six other casino hotels subsequently joined the Hughes empire in Nevada – the Sands, the Castaways, the Frontier, the Silver Slipper and the Landmark in Vegas, and Harold's Club in Reno.

In the process, Hughes – or rather Maheu acting on his behalf – played a key role in prising Las Vegas out of the hands of the mob. Those were especially rip-roaring years. In 1968 Maheu made a $50,000 donation to the Democratic presidential nominee Hubert Humphrey, in cash from the gambling proceeds at the Silver Slipper. In 1970, there followed a $100,000 cash delivery to President Richard Nixon's close friend Bebe Rebozo. In politics, Hughes believed in backing every runner, and Maheu did as he was told.

In December 1970, however, the pair parted in acrimony. A rival group of aides persuaded the sick and shrivelled Hughes to fire Maheu and move to the Bahamas. Two years later, in a telephone news conference called to disown the fake Hughes autobiography by Clifford Irving, the billionaire denounced his one-time alter ego as "a no-good son-of-a-bitch who robbed me blind".

Maheu sued for defamation, and initially won a $2.8m judgement that was overturned on appeal. In 1976, Hughes died, a disfigured wreck of a man – his hair and nails grown monstrously long, it was reported, his arms riddled with broken hypodermic needles, his weight reduced to 90lb (little more than six stone).

Maheu himself had stayed on in Las Vegas, reactivating his former company, and providing consultancy services to mostly corporate customers. He also indulged his epicurean instincts, setting up a Las Vegas branch of a French gourmet cooking society. But to the end he wondered about his relations with his old boss.

Once Maheu did have it out with Hughes, in a rambling, wrenching phone conversation, in which the latter finally explained why they had never met. "After four or five hours of talking, Hughes started sobbing," Maheu recounted. "'Bob, you've exhausted me,' he said, 'there's nowhere left for me to go but the truth. If I let you come up here and see me looking like this, you'd never again be able to represent me with the same accomplishment.' I felt, good God, I'm talking to the poorest man in the world, and I started crying too."

Rupert Cornwell

Robert Aimé Maheu, businessman: born Waterville, Maine 30 October 1917; married 1941 Yvette Dohou (died 2003; three sons, and one daughter deceased); died Las Vegas, Nevada 4 August 2008.