As a result, Anthony Sowell's DNA was never entered into a national database, The (Cleveland) Plain Dealer reported Tuesday.
Eve Mueller, a spokeswoman for Ohio Attorney General Mike DeWine, said the sample, taken while Sowell was serving a 15-year sentence, was sent by mail to a private lab in Virginia that had a contract with the state at the time.
"I don't know if it got lost in the mail or if it got lost in the Virginia lab," Mueller said. "Nobody knows what happened to it after that."
Sowell's DNA was not among 200 samples Commonwealth Biotechnologies recently told Ohio it had found, still untested. The samples have since been tested at the state crime lab.
Sowell is suspected of an April 2009 rape in Cleveland Heights. There is some dispute about whether evidence collected from the victim was tested, although no he would not have been identified as a suspect if it was.
Cleveland police found the bodies of 11 women in Sowell's home in November 2009. At least four of them had disappeared between April and November.