Mayor Anthony A. Williams has asked D.C. police to investigate a breach of security at One Judiciary Square after a dead pigeon was found hanging from a hook outside the window of the mayor's 11th-floor office last week.

Williams was attending a convention in Las Vegas the afternoon of May 23 when a police officer patrolling the building at 441 Fourth St. NW found the pigeon hanging by fishing wire from the roof, so that it could be seen from the mayor's suite.

"Somebody found out I like birds," Williams said yesterday. "I do, but I don't like dead pigeons. . . . To me, it was a breach of security. Obviously, we've got to seal that."

Sgt. Joe Gentile, a D.C. police spokesman, said the department's intelligence division is investigating the incident.

"The police became involved because it appeared strange, and we wanted to check to see if there was any meaning," said Executive Assistant Police Chief Terrance W. Gainer. "Inquiring minds want to know why a dead bird was strung by wires in front of [Williams's] window."

Gainer said he does not believe the bird symbolized a threat to Williams.

"We feel very confident that there is no threat to the mayor," Gainer said, adding that the investigation is close to an end and that he plans to discuss the department's findings with Williams.

The incident, first reported by the Common Denominator community newspaper, has drawn attention to security problems at One Judiciary Square since Williams took office in January. Williams said he has learned that some basic security precautions had not been taken to protect those who work in the building.

The city's Office of Property Management has found that the locks to the building were not changed and that the keys of some staff members of former mayor Marion Barry had not been collected, Williams said.

"The things [D.C. property management director] Kenneth Kimbrough is finding out are that a lot of things haven't been done that should have been done," Williams said. "No question. Basic security."

Williams said that his security detail has not been increased since the incident but that there have been changes that he would not specify.

"You know in this job there is always a risk," the mayor said. "My policy is for the police department to consult with the Secret Service and come through with their recommendations. I don't get involved with these issues."

Kimbrough said government workers at One Judiciary Square have both metal keys and electronic cards to gain access to the building. The cards can be canceled by a computer when an employee leaves government; the metal keys are not as easy to collect, he said.

There are two ways to get to the building's roof: by a service elevator and through a door to a stairway near the mayor's office.

Kimbrough said he is convinced that the intruder was one of about 50 people with keys to the stairway door. He said the person probably entered the stairway, walked up to a 12th-floor room and then onto the roof, where the dead pigeon was tied to a wire and swung over the building's side.

"All the locks to the mayor's suite have been changed," Kimbrough said. "We haven't changed every lock in the building, but we probably will."

The building has 24-hour security, and employees are required to sign in on weekends.

"We don't prohibit people from coming in on the weekends," Kimbrough said. "The presumption is if they come in, they have legitimate business. No one escorts them or follows them around.

"Was it a prank? Was it a message? A disgruntled employee, [an] ex-employee?" he asked. "I don't think anyone knows."