DETROIT (AP) — Detectives are searching for a man who they believe sexually assaulted seven women since New Year’s Day and tried to attack another, Detroit’s police chief said Monday.

The first attack happened before dawn on Jan. 1, and the most recent attack happened at 2:40 a.m. Thursday, hours before volunteers hit the streets to warn women and to circulate a sketch of the suspect, Chief Ralph Godbee said at a news conference.

“We don’t want people to be gripped by fear. … We’re not going to let this monster cripple us,” Godbee said.

The suspect is described as black, in his 30s and about 5 feet 9 inches tall. All of the victims are black, and they range in age from 17 to 33 years old, the chief said.

All of the attacks happened about five miles from downtown Detroit, and in most cases, the victims were waiting for a bus or walking to or from a bus stop, Godbee said.

Police on Monday released two new sketches of the suspect that incorporate facial details gleaned from interviews with his most recent victims.

Godbee said “critical” results from tests on evidence should be available with days, but he declined to elaborate on how they would help the investigation.

Nine men have been questioned and subsequently arrested for other offenses, including parole violations and gun crimes, Godbee said.

The chief especially appealed to men to look out for women who could be vulnerable.

“If we stop the attacks, we’re pleased but we’re not done with our work,” the chief said, referring to an arrest and charges.

Copyright 2011 The Associated Press.