Brookline Police are warning residents of a serial male flasher who has exposed himself to women as they walked on the streets six times since January.

There were two incidents on Jan. 5, one on Jan. 20 and three on April 5, according to police. Authorities believe the incidents are related.

They all happened in the area of Babcock, Pleasant, Freeman and James streets, police said.

The subject is described as a thin, bespectacled white man in his mid-20s with brown or blonde hair and about five-foot-ten in height.

The victims in all of the cases have not been physically assaulted. The incidents usually occur in the evenings between 4 and 9 p.m.

Police have increased patrols in the area and are encouraging anyone who sees anything suspicious to call 617-730-2222.