Six street robberies took place in Harvard's backyard in the last month of 1997, causing Harvard police to issue an advisory bulletin by e-mail to numerous news-groups Dec. 19.

The advisory, which warned the community of the danger, noted that the robberies took place in the 10-day span between Dec. 8 and Dec. 19.

A Harvard graduate student was the victim of one of the robberies, said the advisory, which was also posted in some upperclass houses. The student was robbed and assaulted on Dec. 18 in a parking lot near Rockefeller Hall.

The assailant reportedly had "a strong odor of alcohol on his person."

According to the advisory, the graduate student's assailant is a tall dark-skinned black male, age 25-30, who weighs about 200 pounds.

Two patterns of assault are developing in the other five robberies, the bulletin said.

A duo of "black or Hispanic" men has been "approaching [men] from behind and punching them in the side of the head" before taking their property, according to the bulletin.

Also, a black and a white male have targeted female victims, the advisory said. The assailants reportedly take the women's cash, wallets or handbags.

The suspects are described as six-foot tall males in their early twenties; one is black and one is white.

In the advisory, Harvard police asked anyone with more information on the suspects to contact them.

"We ask you to be aware of your surroundings when walking through or visiting these areas," the bulletin said.

Harvard police spokesperson Peggy McNamara could not be reached for comment yesterday.

All six of the robberies have occurred in neighborhoods bordering Harvard buildings, according to the advisory bulletin.

Two have taken place near Brattle, Sparks and Avon streets, and three have occurred around Bryant, Irving and Hammond streets, the advisory said.

The robbers at the Avon street incident allegedly had a gun, according to the bulletin.

"I live very near the first two [robberies]," said Graduate School Council President Adam P. Fagen in an e-mail which was posted on harvard.general. "Maybe I should be worried."

"Yes, be worried." responded Coordinator of Residential Computing Support Rick Osterberg '96. Osterberg issued the original bulletin to harvard.general.

Osterburg also detailed to the news-groups a Dec. 18 attack on one of his friends, who was found unconscious on Sparks Street by police after the robbery.

An additional robbery was reported by the Somerville police department. This robbery took place on Beacon Street outside of Star Market.