BROOKLINE (CBS) – A third armed robbery in the past two weeks near the Boston University campus has police warning students to be careful.

Brookline police confirmed that a recent graduate of the school was robbed at gunpoint Friday around 5 p.m.

The robbers stole his iPhone, wallet, and keys. It happened around Thatcher and St. Paul streets.

Just a block away, at Egmont and St. Paul Streets, three BU students were robbed on September 25 around the same time. Two other students were held up on September 23 around 3 a.m. about 8 blocks away, at the corner of Hamilton Road and Thorndike Street.

Police say the suspects in all three robberies were three black teenage boys. One showed a gun. BU and Brookline police have added extra patrols to the area.