Ninety years ago today one of the most infamous incidents in US history took place: the St Valentine’s Day Massacre.

While the poetry of the phrase itself lives on, the actual events that unfolded on that dank winter morning in Chicago are often only hazily remembered, if at all.

When the fate of the seven mobsters gunned down by firing squad in the Windy City is recalled, it is usually through the incident’s portrayal in Billy Wilder’s Prohibition cross-dressing comedy Some Like It Hot (1959).

In that film, the executions are witnessed by hapless musicians Joe (Tony Curtis) and Jerry (Jack Lemmon), causing them to flee for Florida disguised in drag as “Josephine” and “Daphne” as part of Sweet Sue’s Society Syncopators, an all-female jazz band whose singer Sugar Kane (Marilyn Monroe) beguiles them both.

As portrayed in Some Like It Hot, the Chicago Outfit are a conspicuously well-tailored collective who style themselves the “Friends of Italian Opera” and are led by “Spats” Columbo, the character played by George Raft, an actor who had so thrilled audiences in the early days of sound cinema in Warner Brothers’ gangster pictures “ripped from the headlines”, starring alongside the likes of James Cagney and Humphrey Bogart.

Al Capone's gangster's paradise Show all 8 1 /8 Al Capone's gangster's paradise Al Capone's gangster's paradise Al Capone Mansion The pool house and pool of the waterfront mansion on Palm Island in Miami Beach, once owned by notorious gangster Al Capone REUTERS Al Capone's gangster's paradise Al Capone Mansion The main entrance of the waterfront mansion on Palm Island in Miami Beach once owned by notorious gangster Al Capone REUTERS Al Capone's gangster's paradise Al Capone Mansion The lanai of the waterfront mansion on Palm Island in Miami Beach REUTERS Al Capone's gangster's paradise Al Capone Mansion The living room of the waterfront mansion REUTERS Al Capone's gangster's paradise Al Capone Mansion One of the bathroom's in the mansion REUTERS Al Capone's gangster's paradise Al Capone Mansion The swimming pool REUTERS Al Capone's gangster's paradise Al Capone Mansion One of the bedrooms in the mansion REUTERS Al Capone's gangster's paradise Al Capone Mansion An exterior view of the building REUTERS

The real facts of the massacre, the last gasp of the Roaring Twenties, are somewhat less glamorous.

The seven victims were members of the city’s Irish-American North Side Gang, a bootlegging organisation led by George “Bugs” Moran. They were murdered as part of a bloody turf war with Al Capone’s Italian contingent, the two factions fighting for control of Chicago’s illegal liquor black market, catering to underground speakeasies since the 18th amendment had banned the production, import or sale of alcohol in 1920.

The two sides had been at war since North Side boss Dean O’Banion was shot in the back of the head while clipping chrysanthemums in his North State Street flower shop on 10 November 1924. When the Chicago Outfit’s leadership was subsequently passed on from the experienced Johnny Torrio to the less even-tempered Capone, violence became a way of life on the city’s streets.

Torrio and Capone narrowly escaped attempts on their lives but O’Banion’s successor, Hymie Weiss, was not so lucky. The St Valentine’s Day Massacre was reportedly planned as a hit on Moran after he had avenged Weiss’s murder by taking out Pasqualino Lolordo, one of Capone’s made men.

On 14 February, the North Siders were set up by an undercover Capone contact, who promised a shipment of Canadian whiskey hijacked from the Italians would be delivered to the SMC Cartage Company garage at 2122 North Clark Street.

Moran’s men arrived before 10.30am to meet the incoming truck but, in a peculiar quirk of fate, the target himself was running late. A police car promptly arrived outside, bearing two men dressed in uniform and two more in civilian clothes. Moran, pulling up just in time to spot the quartet entering the building, quietly moved on.

The four entered the depot, cornered the men and ordered them to line up against a rear wall. A hail of gunfire erupted from a brace of Thompson submachine guns and a shotgun. The perpetrators duly made a getaway in the squad car, never to be identified.

The only survivor was a German shepherd named Highball, his lead tied to a parked car’s bumper nearby.

Five of the seven ‘Bugs’ Moran gang members gunned down by Al Capone’s Chicago Outfit on 14 February 1929 (Rex)

The dead included Moran’s right-hand man and deputy Albert Kachellek, bookmaker Adam Heyer, business manager Albert Weinshenker, two brother enforcers – Frank and Peter Gusenberg – as well as two associates, optician-turned-gambler Reinhardt Schwimmer and mechanic John May.

When the real cops arrived, Frank Gusenburg was still alive despite being riddled with 22 bullets but refused to say who did it, dying in hospital still loyal to the thieves’ code of honour he had lived by.

The killings, reported on every front page in America, provoked a public outcry. “From coast to coast, people suddenly seemed to be reaching the conclusion that a line had been crossed, that the violence had become too much to bear,” wrote Capone biographer Jonathan Eig.

President Herbert Hoover met with city elders and duly instructed his attorney general, William Mitchell, to “get Capone”. Though widely suspected of having ordered the hit, the mobster was careful to be in Florida at the time it was carried out.

His bodyguard, “Machine Gun” Jack McGurn, was arrested and accused of being the mysterious connection who had set up the whiskey plot, but no case could be made against him. He said he had spent the day with his girlfriend, Louise Rolfe, and quickly married her to ensure she could not be pressured into testifying against him. She was thereafter popularly referred to by the press as the “Blonde Alibi”.

Ballistics experts did trace the Tommy guns used in the massacre to the Michigan home of one Fred “Killer” Burke. A career criminal with ties to Egan’s Rats and the Purple Gang – mobs out of St Louis, Missouri and Detroit, Michigan, respectively – Burke went on the run after he was involved in a car accident in December 1929 and killed the investigating police officer, Charles Skalay, in a moment of panic.

Briefly on the FBI’s Ten Most Wanted list, Burke was found hiding out on a farm in Green City, Missouri, when a local man recognised his mugshot in a copy of True Detective magazine. He was imprisoned for the murder of Skalay in March 1931 and died nine years later of a heart attack.

Though the Valentine’s Day killings were never successfully pinned on him, the murder weapons were found in Burke’s possession and he was missing a front tooth, a detail that matched an eyewitness description of one of the ersatz officers spotted fleeing the scene.

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The remaining killers are thought to have come from a St Louis gang known as the “American Boys”.

A criminal named Byron Bolton told the FBI in 1934 the Valentine’s Day hit squad had consisted of Burke and American Boys Fred Goetz, Gus Winkeler, Raymond “Crane Neck” Nugent and Bob Carey, apparently modifying the truth to exclude the fact he himself had served as lookout, hence his inside knowledge. Oddly, the bureau’s director J Edgar Hoover left the matter to local police rather than acting on the tip-off.

Al Capone was finally brought down for tax evasion in 1931, the result of an extensive investigation by the Treasury’s Special Intelligence Unit led by Elmer Irey and the work of agent Eliot Ness and his team of “Untouchables”, men who could not be bribed.