The D.C. Recreation Department fired a 24-year-old night watchman yesterday and pledged to tighten its safety procedures as a result of the drowning of a man who was allowed to swim in the Kenilworth Parkside Pool after closing time.

"We are very sad about what happened. We are searching our management system and searching the events to see what actually went wrong," said D.C. recreation director Alexis Roberson.

Roberson said she is considering posting new warning signs around the city's 19 outdoor pools and requiring night supervisors to visit the pools in person, rather than simply checking with night watchmen by telephone.

An autopsy of Kenneth Ferguson, 25, of 4411 Quarles St. NE, showed the cause of death to be accidental drowning, with no other signs of physical injury, according to the Maryland medical examiner's office.

Ferguson died between 1 a.m. and 2 a.m. Saturday, shortly after a late-night fight at the pool involving lifeguards and a group of neighborhood young people who were allowed in the pool in violation of the 7 p.m. closing time, Roberson said. Ferguson was apparently not involved in the fight, she said.

Ferguson and his brother, Casey Ferguson Jr., 24, were among a small group of people allowed inside the pool office earlier in the evening by their friend, night watchman George Williams, Roberson said. Williams could not be reached for comment yesterday.

Roberson offered an account of the evening based on records kept by night supervisors and written and oral statements given to her yesterday by at least four city employes:

At about 10:30 Friday night, Benny McCottry, the department's assistant director of acquatics, drove past the Kenilworth pool as part of his customary unannounced inspections. He saw about four people in the pool area, stopped to order them out and reprimanded Williams for allowing them in. He left after the unauthorized visitors obeyed his instructions.

The Ferguson brothers, a friend named Robert Sumner, and another friend were visiting Williams later that night at the pool office. When a night supervisor called the pool at 12:23 a.m., Williams reported all was well but did not mention that he had unauthorized visitors.

After 12:23, Williams left the pool, leaving Sumner in charge and telling him and the Fergusons not to let anyone else in the pool. But a group of about 15 entered nonetheless, and many apparently went swimming.

At about 12:45, two city lifeguards, David Branch and Coy Lathan, drove past Kenilworth, spotted the crowd near the pool, and stopped to investigate.

With Williams still away, the lifeguards asked the unauthorized visitors to let them in, but a fight ensued when the lifeguards tried to climb the fence to get into the pool area. There were no serious injuries and the two lifeguards left.

By 1:08 a.m., when a night supervisor called to check in, Williams was still away, but Sumner reported to the supervisor that all was well.

The dead man's brother, Casey Ferguson Jr., said that during the altercation he did not see his brother and thought he had gone into the locker room. But shortly after the fight, the men spotted Kenneth Ferguson at the bottom of the pool. Sumner pulled Ferguson out of the water and D.C. police were called at 1:25 a.m.

"It was just an unfortunate set of circumstances," Roberson said. "We are checking what went wrong." She said Williams was fired for leaving his post and for having visitors.