Kansas Attorney General Steve Six, as well as Riley County and Lawrence police, warn Kansans and students to be cautious and vigilant this month on fall break as a serial rapist investigation continues.

“We’re encouraging Kansans to take extra safety precautions and report any suspicious activity to local law enforcement immediately,” Six, a Lawrence resident and former Douglas County judge, said in a statement Friday morning.

Law enforcement in Manhattan and Lawrence have connected 13 attacks dating back to 2001. Six said last month the man is likely spying on women before engaging in what have been described as lengthy attacks.

Authorities have said the victims, time and manner of the attacks are similar in the string of rapes. All of the rapes in Lawrence and a majority of the rapes in Manhattan have occurred while students were on a break from school.

Six sent out the warning because Kansas State University students are on fall break and have no class Monday. Kansas University’s fall break begins Oct. 15.

The attorney general’s office said when universities are not in session, criminals typically target apartments and other student housing areas. Six urged students who do not travel during the breaks to pay close attention to activities surrounding their homes.

Sgt. Bill Cory, a Lawrence police spokesman, said residents should always lock their doors and not let anyone in their homes they do not know. He also said people should travel in groups if possible and let other people know about their whereabouts at all times.

To report crimes in progress call 911. For non-emergency assistance in Lawrence call 832-7509. Rewards may also be available through CrimeStoppers by calling 843-TIPS.