Shortly before 10 a.m. on September 15, 1934, a dark blue Dodge sedan pulled up to the gasoline pumps at a Warner-Quinlan service station on Lexington Avenue in upper Manhattan. Manager Walter Lyle walked over to the car and filled it with five gallons of ethyl as the man behind the wheel requested. “That’s 98 cents,” the attendant told the driver, who reached into his inside coat pocket and pulled a $10 bill from a white envelope.

Lyle grasped the bill with his greasy hands as his eyes noticed something unusual. “You don’t see many of these anymore,” he told the driver. The motorist had given Lyle a gold certificate, which had been removed from circulation more than a year before when President Franklin D. Roosevelt took the country off the gold standard in response to the hoarding of precious metal during the depths of the Great Depression. “No, I have only about one hundred left,” the driver told Lyle. The suspicious attendant recalled his company’s warning that counterfeiters might attempt to reproduce gold certificates, so as the 1930 Dodge pulled away from the station, Lyle scribbled the vehicle’s New York license plate number—4U13-41—on the bill’s margin.

Three days later, after the service station made its deposit, the unusual bill caught the eye of an attentive teller at the Harlem branch of the Corn Exchange Bank who checked its serial number and made a startling discovery. The bill was connected to the “crime of the century,” part of a $70,000 ransom paid to the kidnapper of Charles Lindbergh Jr., the 20-month-old son of the American icon who completed the first solo, nonstop flight across the Atlantic Ocean in 1927. The bank immediately notified federal investigators, who traced the license plate number written on the bill to a German immigrant carpenter named Bruno Richard Hauptmann who lived in a quiet, leafy residential neighborhood in the Bronx.

READ MORE: 10 Fascinating Facts about Charles Lindbergh

The next morning, police and federal detectives peered through their binoculars as Hauptmann left his apartment in a two-story house and backed his Dodge sedan out of the garage. Seeing that the license plate number was a match, the police pulled Hauptmann over and found a $20 gold certificate from the ransom money inside his billfold. Finally, after tens of thousands of man-hours and countless false leads, an arrest was made in the Lindbergh baby case.

The next day, authorities searched Hauptmann’s garage and found $13,750 of the ransom money hidden inside a dirty oil can, stuffed in a package inside a wall and buried beneath the garage floor in an earthenware pickling jar. Hauptmann insisted he had no connection to the crime that had consumed America since the night of March 1, 1932, when the Lindbergh baby’s nurse discovered that the boy had vanished from his crib in the second-floor bedroom of the aviator’s estate in Hopewell, New Jersey.

The only clues left behind were the muddy footprints leading to an unlocked window, a homemade folding ladder left near the house and a ransom note on the windowsill. A month later at a late-night meeting inside a Bronx cemetery, an intermediary delivered the ransom—a wooden box filled with crisp gold certificates. The man who took the ransom passed along a note that the toddler could be found on a boat called Nelly off the Massachusetts coast. A frantic search, however, turned up no sign of the boy.

Six weeks later, a truck driver discovered the toddler’s decomposed body in a wooded area alongside a road less than five miles from the Lindberghs’ house. An autopsy revealed a fractured skull, and authorities theorized that the kidnapper had accidentally and fatally dropped the boy while climbing down the ladder.

Hauptmann denied he was the perpetrator. He explained that he had been given the money by a deceased business partner and had been hoarding gold certificates based on his experience living in Germany after World War I. “I’m afraid of inflation,” he told police. “I know what inflation was in Germany and I wasn’t taking any chances.” Neighbors had noticed that Hauptmann had suddenly stopped working in 1932. He told them he was “making money in Wall Street,” although few were during the Great Depression.

News of Hauptmann’s arrest remained a secret for more than 24 hours before the news leaked out. Curious throngs descended upon Hauptmann’s house. Hot dog vendors did a brisk sidewalk business as schoolboys picked through the detritus outside Hauptmann’s garage for souvenirs and newsreel planes circled above to gather footage.

At a press conference announcing the arrest, a reporter asked New York City police commissioner John O’Ryan, “In your opinion, does this solve the Lindbergh kidnapping?” The commissioner paused and conferred with Division of Investigation director J. Edgar Hoover and New Jersey State Police head H. Norman Schwarzkopf Sr., father of the general who would lead American forces in Operation Desert Storm nearly six decades later, before responding, “Yes, it will.”

Although Hauptmann was convicted in 1935 of the kidnapping and murder in a sensational trial and executed the following year, even eight decades later numerous people don’t believe that the arrest was the final word on who was responsible for the crime. Prosecutors argued that Hauptmann, who had a criminal record in Germany and was on parole when he arrived in the United States as a stowaway, used his carpentry skills to build the ladder and showed the jury that the grain of the yellow pine on a ladder rail matched that of a board in his attic. Handwriting experts said the ransom note matched Hauptmann’s scrawl.

Until his execution, Hauptmann maintained his innocence. Some believe him. Others believe he couldn’t have acted alone and that he was part of a conspiracy that could have involved the underworld or, according to some, even Lindbergh himself.

READ MORE: Bruno Hauptmann Executed