Harvard police arrested a Boston man early yesterday who they say is responsible for a two-week string of computer and equipment thefts in the Science Center and the Biochemistry Building.

Keith J. Smith, 36, was charged with breaking and entering, possession of burglary tools and larceny over $250. He was apprehended around 9 a.m. after allegedly stealing a Power Macintosh computer from the Biochemistry Building and concealing it in a laundry bag, police said.

In announcing the arrest, police said Smith is the person responsible for the theft of three computers, two computer hard drives and a monitor from the Science Center this month.

"We were very concerned about this...because we did not know how our security system had been compromised," said Franklin M. Steen, the director of the Harvard Arts and Sciences Computer Services.

"If indeed the person arrested is the person responsible for the thefts, we are greatly relieved," Steen said.

Smith was arrested after a cleaning service employee saw the suspect walking down the stairs with a bag slung over his shoulder, according to police reports.

After the employee called police, Harvard security guards Hyon-Won Kim and Mike DeFazio arrived in time to see the suspect fleeing from the building, according to the report.

The guards chased Smith down to the corner of Kirkland and Oxford streets. When they caught up to the suspect and surrounded him, he allegedly punched Kim.

While Kim and DeFazio held the suspect, Harvard police officers Dennis M. Maloney and Kevin M. McCarthy arrived on the scene and arrested Smith.

Smith has not yet been charged with assault and battery on a police officer, although Johnson said this charge might be brought against Smith.

Police said the Power Macintosh computer and Apple Desktop mouse found on Smith belonged to Harvard professor Douglas Melton, Melton could not be reached for comment yesterday.

"The math and physics departments had been hit the hardest by the thefts because they had workstations stolen," Steen said.

"The problem with thefts like this is that it damages instructors' programs because the instructors have to rely on this equipment being there. That's where the real loss is," he added.

The thefts at the Science Center began on January 3, police said. Subsequent thefts at the Science Center and the Biochemistry Building occurred on January 4 and 6.

Steen said most of the equipment stolen had been secured with cables.

Herbert J. Vallier, the police department's assistant director for finance and administration, said he was proud that the Harvard guards had gone "beyond the call of duty" in this case.

"What if [Smith] was armed?" Vallier asked