Authorities in Nye County on Wednesday released images of a second girl found on a videotape that shows sex acts by a man on a girl around 4 or 5 years old.
"It appears to be some kind of peep show" of the girl, estimated to be between 10 and 12 years of age, said Nye County sheriff's detective David Boruchowitz.
Authorities have been unable to identify either of the girls on the videotape or the man.
The older girl did not appear to have been sexually abused on the tape and the footage appeared to have been shot from a different room, Boruchowitz said.
Investigators are also examining whether the two segments were filmed with the same video camera, he said.
A 26-year-old Pahrump man, Darren Tuck, surrendered the tape to Nye County sheriff's investigators Sept. 8, after another man reported seeing it, Boruchowitz said.
Tuck told detectives he found the videotape in the desert outside Pahrump more than five months ago, although Boruchowitz said the tape didn't appear to have been exposed to weather or elements.
Boruchowitz said investigators don't think Tuck made the tape.
Tuck was arrested Sept. 19 on charges of promoting child ornography and possession of child pornography, felonies.
The top charge carries a possible sentence of up to life in prison.
Tuck was released without bail, pending arraignment Nov. 26 in Pahrump Justice Court, a court official said.
Pahrump is a small town 60 miles west of Las Vegas.
The Associated Press generally does not identify or release photos of alleged victims of sexual abuse.