The man accused of kidnapping and killing 5-year-old Samantha Runnion pleaded not guilty Friday as prosecutors investigated additional claims against him in a separate case.

Alejandro Avila, 27, was arraigned in Orange County Superior Court on charges that he raped and killed Samantha after kidnapping her from her Stanton home July 15. A pretrial hearing was set for Sept. 16.

Prosecutors have said that they will seek the death penalty against Avila and not consider a plea bargain.

Meanwhile, one of two girls whom Avila was accused of molesting earlier has made additional claims against him. Avila was acquitted of the earlier charges, which involved the 9-year-old daughter of an ex-girlfriend and a second girl, also 9.

The Riverside County Sheriff's Department is interviewing the girl and other potential witnesses to determine if there is enough evidence to bring a new case against Avila.

Samantha was abducted from in front of her home as she played with a 5-year-old friend. Her nude body was found the next day alongside a mountain highway. Investigators said she had been sexually assaulted and suffocated.

Avila, who is jailed without bail, has denied killing Samantha, saying he was at a mall when the girl was snatched. Officials say DNA evidence found on the girl's body matches that of Avila.