The abandoned Antioch School of Law building on 16th Street NW was damaged last night by a fire that officials said may have been caused by vagrants.

The precise cause of the blaze in the Victorian structure remains under investigation, but fire Lt. Philip Pestone said clothing and other personal items scattered about the building suggested that homeless people may have been using it for shelter.

The squatters may have started the fire while attempting to cook or to warm themselves, he said.

Firefighters said they escorted one apparently homeless person out of the building before extinguishing the fire shortly after 8 p.m. No injuries were reported in the incident.

The Antioch building, in the 2600 block of 16th Street NW, has a "for sale" sign in its front yard and appears dilapidated from the outside. It was sold for $1.5 million when Antioch School of Law closed in 1988. The buyer, Crescent Construction Co., had planned to convert it into 88 condominium units.

But fire officials said there were no signs in the building last night that any construction had taken place.

The law school shut its doors because of lack of funds and problems with accreditation 16 years after opening as a "public interest law firm" that trained students by allowing them to practice on cases of low-income clients and special interest groups.

Faculty and student leaders at the District campus had a stormy relationship with Antioch's main campus in Yellow Springs, Ohio. Its enrollment fell in the 1980s, and in 1985 the American Bar Association threatened to revoke its accreditation.