Five Men are Arrested for Trying to Bug the Watergate Complex

On 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). He took the tape off, and thought nothing of it. An hour later, he discovered that someone had retaped the locks. Willis 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. The five 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) and the trial judge, John J. Sirica, suspected a conspiracy involving higher-echelon government officials. In March 1973, James McCord wrote a letter to 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.

http://en.wikipedia.org/wiki/Watergate_scandal