WEST LAFAYETTE, Ind. - A string of three strong-armed robberies on the campus of Purdue University could be connected, police said.

The robberies happened over the weekend -- at 9:40 p.m. Friday in the 1000 block of Third Street; at 4:29 a.m. Sunday in the 600 block of North Russell Street; and at 12:30 a.m. Monday in the 300 block of Centennial Mall Drive.

In the first two robberies, the victims were walking alone when they were approached from behind and assaulted. In the third incident, two people were attacked and robbed.

One victim was treated for minor injuries, police said.

"We want anyone who saw anything they think might have been related to call the police department," Purdue Police Chief John Cox said in a news release. "We also want people to be vigilant, to be aware of what's going on around them and report anything suspicious to the police."

Anyone with information can call the Purdue Police Department at 765-494-8221 or its anonymous tipline at 765-496-3784.