Harold Titus Jr., 60, U.S. attorney for the District of Columbia from 1971 to 1973, and a federal prosecutor for more than 20 years, died Jan. 17 at Suburban Hospital in Bethesda after a heart attack. He lived in Sumner.

Mr. Titus joined the U.S. Attorney's Office in 1950. He was appointed principal assistant of the office in 1969, and became U.S. attorney after the resignation of Thomas A. Flannery.

Mr. Titus retired in 1973 for reasons of health.

As U.S. attorney, he directed one of the nation's two busiest and most important federal prosecution forces. His 140 lawyers faced 12,000 war protesters, implemented the controversial preventive detention provision of the D.C. Crime Act, and prosecuted hundreds of felons.

He gained a reputation among fellow prosecutors as a hard-nosed opponent of crime and one of the toughest fighters in the courtroom. As he rose in responsibility, he also became known as a man who supported his subordinates and their decisions.

In a 1972 interview with The Washington Post, he said that he disliked "the liberal-minded jurist--the kind of person," he said, "who has found excuses to criticize policemen making split-second decisions at the risk of their lives."

He was disliked by some defense attorneys, and seemingly relished the fact. A reporter once started to ask a question with, "Defense attorneys say . . . "

"That I am a bastard?" Mr. Titus interjected. "I consider that a compliment."

His goals as U.S. attorney included emphasizing the work of his major crimes unit, which handled narcotics, gambling, and homicide investigations, and the fraud unit, which investigated white-collar crime.

Mr. Titus was acting U.S. attorney during the Mayday Vietnam war protest in 1971 in which 12,000 demonstrators were arrested, nearly all of whom were released without prosecution. He told a Post reporter in a 1973 interview that the mass arrests were not wanted by anyone, especially the police, but that they had no alternative.

He was U.S. attorney in the early days of the Watergate scandal, before the office of the special prosecutor was established. His prosecutors secured the conviction of the men who broke into the Democratic Party offices at the Watergate.

Mr. Titus was a lifelong area resident. He was born in Washington and was a graduate of Georgetown Prep School. He graduated from Georgetown University and its law school. He served with the Navy in the Pacific during World War II.

He was a member of the University and Army Navy Country clubs, and belonged to the parish of Little Flower Catholic Church in Bethesda. In recent years he had done consulting work for the Republican Party.

He leaves no immediate survivors.