(CNN) -- Ohio authorities are conducting DNA tests on evidence to determine if additional victims were inside the Cleveland house of Ariel Castro, accused of holding three young women captive for 10 years, officials said Friday.
"The state's crime lab has received additional evidence to test in the Ariel Castro Case," said Dan Tierney, spokesman for Ohio Attorney General Mike DeWine.
DNA tests will be conducted "to determine whether there are additional victims," Tierney told CNN.
He declined to say what kind of evidence was turned over and whether it was found inside or outside the house.
Since the case began, investigators have been looking for evidence of aborted fetuses and of any other girls or women who may have been kidnapped or held captive in the house.
Castro faces 329 charges, including one count of aggravated murder for causing the unlawful termination of a pregnancy.
This week, Castro entered a not guilty plea to all charges, including 139 counts of rape and 177 counts of kidnapping Michelle Knight, Amanda Berry, and Georgina "Gina" DeJesus. Castro fathered a daughter with Berry, according to authorities.
Police have said Knight was impregnated allegedly by Castro five times, but he would punch her in the stomach, which resulted in miscarriages and termination of all the pregnancies.
The state's crime lab has been testing DNA evidence, fingerprints, and firearms on behalf of Cleveland police, according to Tierney.
According to forensic experts, it's common practice to crosscheck DNA samples from any crime scene and compare them to victims and others to determine whether there is any DNA not accounted for.