Updated 12/21/2011 7:55 p.m.

Austin-area detectives are still searching for the individuals responsible for a string of armed robberies and sexual assaults on the West Side.

Since August, there have been 11 related attacks spanning the 11th, 12th and 15th Police Districts, said Officer Darryl Baety, a Chicago Police Department spokesman.

In mid-October, West Side aldermen, police and the Area 5 detective division hosted a community meeting to alert residents about the attacks. The first attack occurred on Aug. 28 and the most recent one took place on Dec. 5.

One or two African-American male offenders have approached females exiting their cars, walking on the sidewalk or entering their homes at gun point between the hours of 3 a.m. to 6 a.m., Baety said. The offenders, he adds, often grope or sexually assault their victims.

The most recent armed robbery and sexual assault occurred Dec. 3 in the 900 block of North Lockwood Avenue. The offenders are described as being 20 to 30 years old, 5-foot-5 to 6-feet tall, 130 to 190 pounds, and wearing a mask, skull cap, or a black hood and dark clothing. Residents in the area should be vigilant, Baety said, when outside in the early morning-they’re also advised to contact the police or the area detectives if they witness any suspicious activity.

Residents are encouraged to call the Area 4 Detective Division (312-746-8253) or Area 5 Detective Division (312-746-8362) with any information about these crimes.

Suspect wanted in sexual assault of teen girl

Chicago police are also looking for man who recently sexually assaulted a teenage girl in the Austin neighborhood.

The attack reportedly happened on Dec. 15 at around 3:10 p.m., according Chicago Police News Affairs. Police say an unknown male approached and inappropriately touched a 13-year-old girl as she walked down the 4800 block of West Jackson.

The offender exited a black and green van to approach the girl. According to police, he attempted to talk to the teen and then grabbed the hood of her jacket. When she turned around, the offender touched her inappropriately, police say. The girl bit the offender’s hand and then ran off.

The man is described as black, between 20 and 30 years old, with brown eyes, a beard, and black hair in a twist. He was wearing a black jacket and black sweat pants. Police say a second unknown offender was inside the van when the assault occurred. Anyone with information is encouraged to call Area 5 Detectives (312-746-8282).

Terry Dean contributed to this story 

Robberies since August

Aug. 28, 5:45 a.m. – 1100 block of North Lawndale

Sept. 25, 3:30 a.m. – 800 block of North Harding

Sept. 25, 4:47 a.m. – 5500 block of West End

Sept. 28, 3 a.m. – 4700 block of West Maypole

Sept. 28, 3:18 a.m. – 3800 block of West Monroe

Sept. 28, 4:25 a.m. – 5400 block of West Crystal

Oct. 1, 4:45 a.m. – 2200 block of West Monroe

Oct. 2, 3:15 a.m. – 900 block of North Leamington

Oct. 2, 5:25 a.m. – 5400 block of West Fulton

Oct. 7, 4:40 a.m. – 600 block of North Leamington

Dec. 3, 5:30 a.m. – 900 block of North Lockwood