The Lawrence Police Department is investigating a sexual assault that occurred about 3:30 a.m. Saturday in west Lawrence.

Cpt. Dan Affalter said a 20-year-old Lawrence woman, a Kansas University student, reported she had been sexually assaulted by someone who had entered her apartment in the 3800 block of Clinton Parkway.

The suspect was described as a white man, approximately 5 feet 9 inches tall and weighing approximately 160 pounds. The suspect left the area in an unknown direction, according to police.

Police are investigating this attack as well as three other cases since 2004, which may be related. In all three cases, the suspect, who was armed with a weapon, entered residences in Lawrence and raped a total of four women. A suspect description from all cases was compiled, and the suspect is described as a white male from 25 to 40 years of age ranging from 5 feet 9 inches to 6 feet tall, with a slim build.

Police are asking anyone with information to call the Lawrence Police Department Investigations Division at 830-7430 or the Douglas County Crime Stoppers TIPS Hotline at 843-TIPS.