In 1969, heroin was stolen right under the noses of the police.
This is how The Geneva Times (Dec 15, 1972) reported it:

"NYC Police Chief Hints Heroin Heist Inside Job"

"Police Commissioner Patrick V. Murphy ruefully announced Thursday that 57 pounds of heroin worth up to $12 million — originally seized in the case popularized by the film "The French Connection" — had been stolen from the New York City Police Dept. The Commissioner, obviously embarrassed and angry, said its his knowledge it was the largest amount of heroin ever lost by a law enforcement agency, and it could well have been an inside job. Murphy said property clerk's receipts show the notation on Sept. 29, 1969 "a detective removed the narcotics for a district attorney." But the commissioner added the detective's signature now appears to be false, and the badge number he gave on a receipt never was issued to any member of the department.
The property clerk's records show no further movements of the narcotics after Sept. 29, 1969. In November, the police audited it's supply of narcotics seized in arrests. The drugs often are held for years as evidence in lengthly court proceedings. And when the "French Connection" heroin appeared to be missing on Nov. 17, detectives carefully combed the property clerk's vault. Four days later, plastic bags labeled heroin from the case were discovered. But analysis by the police crime laboratory showed 57 pounds was just white powder and not a narcotic.
"This is a scandal in the department," Murphy declared, his top commanders seated alongside him at a crowded news conference. The stolen drug was part of 73 pounds of heroin confiscated in the police raid on Feb. 25, 1962. It was smuggled into the United States from France in secret panels in an automobile. The loss was almost half the total amount of heroin, 119 pounds 10 ounces, captured by the police in New York in 1962. The missing heroin was stored in a vault in the property clerk's office just north of Manhattan's central police headquarters.
After the initial seizure, the "French Connection" heroin was delivered to various courts and laboratories for evidence and for analysis.
The Commissioner, who joined the department on Oct. 9,1970, said because the heroin traveled to different courts and government agencies it provided an opportunity for sbustitutions — which would make the investigation more difficult."

/// According to Special State Prosecutor Maurice Nadjari, Vincent Papa was the mastermind of the heist. But Nadjari could not prove it. Already in prison for a major drug violation, Papa, who was a reputed soldier in the Lucchese Family, was in 1973 indicted for criminal contempt charges for refusing to answer grand jury questions about the stolen narcotics.
Nadjari also hinted that police officers were the actual culprits of the crime working in cahoots with the Mafia. To my knowledge, and correct me if I´m wrong, the crime was never solved. Vincent Papa was stabbed to death in prison in 1978.

Speaking of the film "The French Connection", here´s a trailer from the hit movie (1971).