Ten people have been robbed on the streets surrounding Boston Common and nearby in the South End since April 1 in crimes that appear to be related, police said.
The spate of robberies has prompted Massachusetts Convention Center Authority officials to place more security guards in and around its Boston Common Garage and police to step up car and bike patrols near the Common.
None of the victims, all of whom are men, were hurt during the robberies, police said. Yet officials are calling on people to be extra vigilant, especially at night, when most of the robberies occurred. Police believe virtually all of the robberies involve one suspect, a man they describe as a black male, 5-foot-10 to 6 feet tall, in his 30s or 40s, with a noticeable gap in his front teeth. Police said the man appears disheveled, and they believe he may be homeless.
Police said some of the robberies were conducted by groups of men, who included the gap-toothed suspect. Police did not have descriptions of other members of the groups, who they said may be targeting people out late at night.
Most of the robberies occurred within a block of Boston Common, but three of them took place not much farther away in the South End, according to police, who said one robbery involved a knife and another a box cutter.
The most recent robbery occurred Friday near a
Local residents said they were concerned by the reports. David Seeley, an architect and member of the Leather District Neighborhood Association, said he has seen an increasing number of suspicious-looking men hanging out on Essex Street, near where police say one of the robberies occurred.
''There are groups of people hanging out and giving you the evil eye," he said. ''It's the closest route to take to my kid's school, and you certainly wonder whether, as a parent, you're being irresponsible bringing your kid through there."
Seth Gitell, a spokesman for Mayor Thomas M. Menino, declined to comment on the robberies, saying it was a police matter.
Boston police spokesman Michael McCarthy urged people who are going to be in Boston at night ''to be aware of their surroundings."
''Anybody can be a victim," he said. ''People who tend to victimize people, they look for opportunity [when] there's not many witnesses."
Last month, two women were robbed as they attempted to exit the underground parking garage at Boston Common.
Kevin Maguire, chief of security for the Massachusetts Convention Center Authority, which runs the garage, said his agency has reorganized the placement of security guards to ensure each garage exit is better patroled. After midnight, drivers are directed to exit the garage at an entrance where a guard is on duty. ''We have significant patrols inside the garage itself," he said. ''We want to assure that our patrons are safe and secure in that environment."
Several of the robberies occurred at ATM machines, and seven occurred between 11:45 p.m. and 7:30 a.m., police said.
Two robberies near the 7-Eleven at Tremont and Stuart streets involved what witnesses described as a group of men surrounding and then robbing a victim, according to police. Robberies also occurred near the intersections of Stuart and Arlington streets, Kneeland and Washington streets, Berkeley and Boylston streets, and Providence and Berkeley streets, while others occurred on Dartmouth Street, East Berkeley Street, and near Perry and Washington streets.
Police also released statistics showing a slight rise in overall robberies and attempted robberies citywide. From Jan. 1 to April 21, police tallied 730 robberies and attempted robberies in Boston, compared with 692 during the same period last year, the statistics indicate. Police Area A, in which Boston Common is located, had 127 robberies or attempted robberies so far this year, as opposed to 133 during the same period in 2005.
Ralph Ranalli of the Globe Staff contributed to this report. Adrienne P. Samuels can be reached at email@example.com.