Watergate: The President-toppling scandal triggered by a piece of tape

It all began when a vigilant night watchman noticed a piece of tape on a door of the building where the Democratic National Committee's headquarters was located in Washington in June 1972.

Calling the police, he triggered the Watergate scandal that would topple the presidency of Richard Nixon, the only US leader ever to resign.

The tape, it turned out, was placed during a break-in by five men who had been tasked by officials with ties to the White House with placing microphones and taking pictures of documents to find compromising information on Nixon's opponents.

The night of June 16-17, 24-year-old security guard Frank Wills was making the rounds at the Watergate buliding complex when he noticed the tape on a door that prevented it from locking.

At first, he didn't worry, removing it and continuing working.

But when he returned, so had the tape, leading him to suspect a break-in had occurred. Wills -- who plays himself for a few seconds at the beginning of the film "All the President's Men" that chronicles the saga -- immediately called police.

"Found tape on door. Call police to make a inspection," he wrote in a building security officer's log, which has been preserved by the US National Archives.

Police officers arrived on the scene within "a minute, a minute and a half," one of them, John Barrett, told ABC News in 2017.

He and fellow officer Paul Leeper were dressed in plain clothes, and were even a little scruffy.

That worked in their favor, as Alfred Baldwin, the man who was supposed to be keeping watch during the break-in, did not seem to notice them right away. His attention may have been focused on the movie "Attack of the Puppet People," which was being shown on TV.

"He was glued to the TV set," and by the time he warned the others, "it was too late and they had to run and hide like rats," Barrett said.

Once inside the office, the two officers found tape on several doors, realizing that something fishy was going on.

"Our adrenaline is pumped," Leeper told ABC.

They found ransacked offices and suspected that the perpetrators were still present, and started to search for them room by room.

Suddenly, Barrett saw an arm. "It scared the living bejeezus out of me," he said.

"I scream something to the effect, 'Come out with your hands up or I'm gonna blow your head off.'"

"Ten hands went up, and they came out, and that's where the arrest occurred," Barrett said.

Across the street, Baldwin had his ear to a walkie-talkie. "In a very soft whisper, I heard a voice: They've got us," he said.

The 10 hands belonged to James McCord, Virgilio Gonzalez, Frank Sturgis, Eugenio Martinez and Bernard Barker.

The police soon realized that this "was not your normal, typical burglary," Barrett said.

Not only were the burglars dressed in suits and ties, but they had bugging devices, tear gas pens, numerous rolls of film, locksmith tools, and thousands of dollars in hundred dollar bills, he said.

On June 18, The Washington Post published its first article on the subject. It was bylined Alfred E Lewis, the reporter covering the police. But its list of contributors at the end also included the names Bob Woodward and Carl Bernstein.

The two young reporters took over, investigating the details of the case that brought down Nixon's presidency two years later, and winning the prestigious Pulitzer Prize for their work.