The Harvard University Police Department (HUPD) now has "solid leads" in the "unprecedented" crime wave in the Yard dorms, HUPD spokesperson Peggy A. McNamara said yesterday.

McNamara said detectives now believe that the crimes in Matthews and Thayer Halls are the work of a single perpetrator.

"He's like a shark and he's come into a feeding frenzy," she said.

McNamara said HUPD has refined its description of the suspect and is seeking a 5-foot 10-inch light-skinned black male between 18 and 22 years old. Past descriptions had only referred to the Thayer burglary and omitted the suspect's age.

HUPD also said for the first time yesterday that the credit cards taken over the past three weeks have been used since they were stolen, but did not release the locations of their use.

Matthews Hall was first burglarized on Oct. 3, and now a total of seven Matthews suites have been robbed. On Oct. 12 a student entered his Thayer Hall suite while a robbery was in progress, and police suspect the same man committed all the crimes.

HUPD believes that a larceny last week in Weld Hall is not related to the other crimes.

According to McNamara, HUPD has stepped up Yard patrols and added undercover officers in the wake of the incident.