An arsenal of weapons and explosive devices was found in the Brooklyn Heights apartment of a Columbia University professor yesterday morning after the professor’s roommate accidentally shot himself, police said.

Police said they removed seven homemade pipe bombs, a 9 mm handgun, a rifle, a crossbow and arrows, a machete, ammunition, gun silencers, and several bulletproof vests from a small one-bedroom apartment at 58 Remsen St. that neighbors say is owned by Michael Clatts, an AIDS researcher at Columbia’s Mailman School of Public Health and the National Development and Research Institutes.

The arsenal was discovered after a man who also lived in the one-bedroom attic apartment, identified by sources as Ivaylo Ivanov, 31, shot himself in the hand.

After telling police officers on patrol on Montague Terrace that someone had shot him at around 1 a.m. on Sunday, he was taken to Long Island College Hospital, where he later admitted to police that he had shot himself.

A downstairs neighbor, Penny Kaufman, said she escorted police to the fourth floor apartment at around 3:30 a.m. yesterday to help them subdue the two men’s dog. Through the door of the apartment, Ms. Kaufman, a legal secretary, said she saw a handgun and several bullets lying on a desk chair near the door. She also saw blood smeared on a wall near the light switch and towels balled up in the sinks and bathtub.

“The apartment was in total disarray,” she said.

Then she said she heard one of the police officers say, “These are pipe bombs.”

Residents of 58 Remsen St., along with two neighboring buildings, were immediately evacuated and ushered into the lobbies of nearby structures. They were prevented from returning home for about seven hours as police sought a search warrant and bomb squad units swarmed the streets.

Police said they were doing routine checks into whether Mr. Ivanov was linked to terrorist groups, and would be testing the bombs, which had fuses and powder, to see if they were operable. Police said one of the suspected bombs had been inserted into a toy football, and throughout the day they removed evidence from the apartment, including a laptop computer, a video game console, and tools for drilling into pipes.

Residents expressed amazement and disbelief that the incident had occurred on the brownstone and tree-lined street less than two blocks from the Brooklyn Heights Promenade, and alternately described the two men as congenial and odd.

Neighbors said Mr. Clatts, who had owned the apartment for about a decade, was often away on business trips and may have been out of the country this weekend. He is a professor at the University of Puerto Rico, an associate professor at Columbia, and is also conducting a study on HIV in Vietnam, according to the Web site of the National Development and Research Institutes, a Chelsea-based nonprofit organization with which Mr. Clatts was also affiliated.

A spokesman for the police department, Assistant Chief Michael Collins, said that police did not have any reason to believe as of yesterday evening that Mr. Clatts “had anything to do with this.” They said they believed that Mr. Clatts had a separate living area and bed inside the apartment.

As one of the first social scientists to undertake AIDS research in the early 1980s, Mr. Clatts had done studies for the National Institute on Drug Abuse, including one that was interrupted when the NDRI offices in the South Tower of the World Trade Center were destroyed in the terrorist attacks of September 11, 2001.

Ms. Kaufman described Mr. Clatts as an “eccentric professor” and “brilliant.”

Mr. Collins said witnesses who had entered the apartment recently had not noticed anything unusual, suggesting that the weapons might have been acquired while Mr. Clatts was away.

Ms. Kaufman said Mr. Ivanov had once showed her the crossbow, however.

“I thought the situation may have been a little unusual,” Ms. Kaufman said, noting that other than occasional chats with Mr. Ivanov about their mutual interest in horses and occasional squabbles with Mr. Clatts over co-op board issues, she had not interacted often with the pair.

Mr. Ivanov, who police and neighbors believe is originally from Bulgaria, moved into the building about six years ago, and another resident, James Robinson, 45, who is an opera director, called Mr. Ivanov an “excellent neighbor.”

When Mr. Clatts was home, the two men often went on camping trips upstate, loading bags of supplies and the dog, a German shepherd mix, into their car, Ms. Kaufman said.

Neighbors and police said Mr. Ivanov did not appear to have a job outside of the home, although Mr. Robinson said Mr. Ivanov had once mentioned working for American military forces in Bosnia.

Police said Mr. Ivanov’s criminal record consisted of a few petty larceny arrests beginning in 2000. He remained in police custody, but had not been arrested or charged as of yesterday evening. Police said they did not know where Mr. Clatts is.