Federal authorities acknowledged Tuesday that they had had a DNA sample from home invasion and rape suspect Delmer Smith III during the months detectives say he attacked numerous women in their homes in a violent crime spree.

But Smith's DNA had never been entered into the FBI's DNA databases, so authorities in Florida's Sarasota County didn't get a match from DNA they say Smith, 38, left behind in four incidents.

FBI spokeswoman Ann Todd said Smith's DNA was part of a huge backlog in entering DNA collected from federal prisoners into the databases, which are used regularly by local law enforcement agencies across the nation. Smith was a federal inmate until late 2008 for a 1995 bank robbery.