On the evening of June 17, 1972, Frank Wills, a security guard at the Watergate Complex, noticed tape covering the latch on locks on several doors in the complex, leaving the doors unlocked). Willis took off the tape, and thought nothing of it. An hour later, he discovered that someone had retaped the locks. Wills called the police and five men were arrested inside the Democratic National Committee's (DNC) office. The five men were Virgilio González, Bernard Barker, James W. McCord, Jr., Eugenio Martínez, and Frank Sturgis. They were charged with attempted burglary and attempted interception of telephone and other communications. On September 15, a grand jury indicted them and two other men (E. Howard Hunt, Jr. and G. Gordon Liddy) for conspiracy, burglary, and violation of federal wiretapping laws.
The men who broke into the office were tried and convicted on January 30, 1973. After much investigation, all five men were directly, or indirectly, tied to the 1972 Committee to Re-elect the President (CRP, or sometimes pejoratively referred to as CReeP). The trial judge, John J. Sirica, suspected a conspiracy involving higher-echelon government officials. In March 1973, defendant McCord wrote a letter to Judge Sirica, claiming that he was under political pressure to plead guilty and he implicated high-ranking government officials, including former Attorney General John Mitchell. His letter helped to elevate the affair into a more prominent political scandal.
The FBI connected the payments to the burglars to a slush fund used by the 1972 Committee to Re-elect the President. As evidence mounted against the president's staff, which included former staff members testifying against them in an investigation conducted by the Senate Watergate Committee, it was revealed that President Nixon had a tape recording system in his offices and that he had recorded many conversations. Recordings from these tapes implicated the president, revealing that he had attempted to cover up the break-in. After a series of court battles, the U.S. Supreme Court ruled that the president had to hand over the tapes; he ultimately complied.
Following is a YouTube video of Fred Thompson (then a lawyer for the Watergate Commission, before his days in the Senate and on Law and Order) questioning James McCord at the Senate Watergate hearings on May 22, 1973:
Facing near-certain impeachment in the House of Representatives and a strong possibility of a conviction in the Senate, Nixon resigned the office of the presidency on August 9, 1974. His successor, Gerald Ford, issued a pardon to President Nixon after his resignation.