Sonny Grosso, who has died aged 89, was a New York detective whose seizure of a huge consignment of heroin inspired the Oscar-winning film The French Connection (1971), in which he was played by Roy Scheider; with his partner Eddie Egan (Gene Hackman), Grosso also contributed extensively to the script, injecting new verisimilitude into the portrayal of police work on the screen.
As seen in the film, the break-up of the drugs ring began by chance in 1961 when Grosso and Egan, after 27 hours on duty, went to relax at a Manhattan nightclub, the Copacabana. There they saw a dealer they knew, Patsy Fuqa, and on a hunch decided to tail him. So began the unravelling of a trade which had been growing since the 1930s. Much of the import of heroin into the US was controlled by Corsican gangsters who by the early 1960s were smuggling in 110lb of the drug from Marseille every six weeks, contributing to the growing crisis in America's inner cities.
"Bullets" Egan and "Cloudy" Grosso were an unorthodox but complementary pair. The former was Irish, something of a womaniser, a bully, and an egomaniac with a flair for drama. The film scene in which Hackman dresses up as Santa Claus to make an arrest was true to life. This theatricality would surprise malefactors, allowing Grosso, who was of Italian descent, to make what would be a record number of arrests by the time he retired in 1976 and began to carve out his own career in Hollywood.
"Eddie was always an actor, I was always the producer," Grosso reflected of their respective roles in their partnership. Nevertheless, if he was aware of Egan's flaws, he was never less than loyal, playing along for instance when Egan invented details for the press - such as having lowered Grosso into a sewer to retrieve a lost key needed for a case.
The pair eventually broke up the French gang, confiscating an unprecedented haul of 112lb of heroin with a street value of $32m. The bust was chronicled in 1969 by the writer Robin Moore. When the director William Friedkin began in 1971 to film a lightly fictionalised version of Moore's book, he hired Egan and Grosso as consultants. They would spend the day on set, largely in Brooklyn, and work shifts at night.
Grosso, in particular, was keen that the gritty reality of their lives - far removed from the "Just the facts, Ma'am" approach of clean-cut shows such as Dragnet - should be properly depicted. So he took Friedkin, Hackman and Scheider along with him and Egan on raids in Harlem.
Friedkin was so impressed by Grosso that when filming wrapped he drove him over to where Francis Ford Coppola was shooting The Godfather and insisted Grosso be hired as its adviser. "I found locations, showed them how to search, hammered the crowds, drove cars and provided 75 cops as extras, as well as members of my family for the wedding scene," he said.
As he had in The French Connection, Grosso played a small part in The Godfather. It was also his gun which was used by Al Pacino in the scene in which, having been frisked, Michael Corleone retrieves a weapon hidden in a restaurant bathroom to kill two rivals ("They took out the real bullets first," said Grosso).
The French Connection went on to win five Oscars, including that for Best Film, although Grosso did not go to the ceremony in Los Angeles; he had a fear of flying.
One of four children, Salvatore Anthony Grosso was born on July 21, 1930 and grew up in East Harlem, then an Italian neighbourhood. His father, a truck driver, died when Sonny was 14, and as the only son he became the breadwinner. He was drafted into the Army after high school and spent two years in Korea as a radio operator during the conflict before being invalided out with a knee injury. Grosso then drove a postal lorry before joining the police force in 1954.
The fame which came to Egan and Grosso after Moore's book led to jealousy within the police, according to Grosso, and they were split up and assigned to different departments. He subsequently left the force and worked as an adviser to TV shows such as Kojak. Grosso also appeared in several films and became a producer himself, notably of the 1980s Canadian TV series Night Heat.
He wrote several books about his experiences, among them Point Blank (1978), which dealt with police corruption, and Murder at the Harlem Mosque (1977), focusing on the tension between law enforcement and racial politics. In 1980 he was reunited with Friedkin and Al Pacino on Cruising (1980).
Sonny Grosso, who died on January 22, is survived by his partner of more than 40 years, Christina Kraus, and by a son and three daughters.