St. Paul Pioneer Press

The numbers might seem alarming: more than 3,000 rape kits sitting on shelves, untested, at law enforcement agencies across the state. And for more than 9 percent of those cases, the reason for not testing is "unknown."

But police are quick to explain that a reasonable explanation often exists for not testing evidence collected after a sex assault is reported: Sometimes victims do not want to move forward with a case. Sometimes the suspect's identity is not in question. Sometimes prosecutors decline to file charges.