The law goes into effect on October1. Also, by October 15, law enforcement agencies must provide the crime lab with all untested rape kits.
There are at least 4,000 untested rape kits in Illinois.
"DNA evidence is incredibly powerful, but if we are not testing it, we're not getting that evidence. And so often times, when we hear, ultimately, charges are not going to be filed, that doesn't mean a rape hasn't been committed. You test that DNA and you might find matches already, people who have committed similar crimes," said Illinois Attorney General Lisa Madigan.
No new funding was provided for the new law. When a similar measure went on the books in New York, the state's 30 percent arrest rate jumped to 70 percent.