DENVER (CBS4) – A man accused in a series of cold case rapes has been charged in a new case.

Lynn Kimbrough with the district attorney’s office said William Costello, 47, has been charged with second-degree kidnapping and two counts of sexual assault in connection with an assault that took place in July 2011.

“The charges allege that on July 30, 2011, Costello assaulted a 31-year-old woman in the area of 16th and Steele Street in Denver,” Kimbrough said in a statement. “The two were acquainted with each other through a mutual friend.”

According to Kimbrough, Costello was first arrested and charged in July 2012 after and assault on an at-risk adult. Costello’s DNA was taken pursuant to Katie’s Law and was then linked to three unsolved sexual assault cases occurring in 2008, 2010, and 2011.

Costello’s bond was set at $100,000 in the new case. He is scheduled to appear in court on March 14 to be formally advised of the new charge.