Frank Wills, the night watchman who discovered the 1972 Watergate burglary, which ultimately led to President Richard M. Nixon's resignation, died on Wednesday. He was 52 and lived in North Augusta, S.C.

Mr. Wills, who struggled with celebrity and joblessness after being hailed as hero, died at University Hospital in Augusta, Ga. Friends told The Augusta Chronicle that he had suffered from a brain tumor.

Mr. Wills, a 24-year-old security guard at the Watergate office building in Washington, was working the midnight shift on June 17, 1972. He discovered tape over a lock on a basement door, and thinking some worker had left it to make it easier to get in and out, he removed it.

On another inspection round, he found the lock taped over again, and called the police. They locked the doors, turned off the elevators, and started checking darkened offices. About 2 a.m., at the sixth-floor headquarters of the Democratic National Committee, they found five men: Bernard L. Barker, Virgilio Gonzales, Eugenio Martinez, James W. McCord Jr. and Frank Sturgis.