The Boston Police Department issued a robbery warning last week for the Mission Hill and West Fens areas. According to a release, two robbery patterns have been identified over the past two months, leading police to believe repeat offenders may be working those areas.

There have been a total of 13 robberies in the past two months in the West Fens area, near Park Drive and the Landmark Center, according to the release. Eleven were street robberies, and the other two occurred in businesses. All incidents took place between 10:30 p.m. and 5 a.m., with the majority taking place between 11 p.m. and 1 a.m. Police report two patterns in the area, one involving a Hispanic male suspect, and one involving a group of black males.

In the same period, there were 19 robberies in the Mission Hill area, 17 of which were street robberies. The majority of the incidents took place between 9:30 p.m. and 3 a.m., and in 13 of the incidents, the robberies were committed by groups of 2-5 suspects, most often black males. Victims were assaulted in seven instances.

Jim Ferrier, associate director of Public Safety at Northeastern, cautioned students against walking alone, and urged them to take a cab at night or walk in well-lit areas.

“There is safety in numbers,” Ferrier said. “It’s extremely rare for someone to get robbed when there are two or three or four of them. It’s people walking alone who get mugged.”

Ferrier pointed out that crime is up in most areas of Boston, and students should be cautious wherever they walk.

“The city is going though a real spike in youth crime,” he said. “Most of it is very parochial, where the Boston city youth are committing crimes against themselves.”

Nonetheless, he cautioned that a student walking alone in the dark is easier prey than a group or even an individual in plain view.

“Don’t cut through the Fens in the middle of the night. Take a cab,” he said. “There’s something about street smarts and common sense.”