It depends on how much information they can get without torture. It seems highly unlikely the tape was found out in the desert. The police can learn a lot by examining the tape, making the suspect show them exactly where the tape was allegedly found.
It's a matter of how much they can learn about who made the tape, how it was distributed and how it wound up in the suspects hands, and how was it that another man came to see it? Did the suspect charge him to see it, or show it to him in the hopes of selling it?
There's a lot of information the suspect may not know. Torture under those circumstances can't reveal anything. But if it becomes clear that he has information about the matters posed above....at least the threat of torture would be a useful tool.
For most crimes, I wouldn't advocate this type of police SOP. But anything to do with children being abused or exploited sexually is so sick that it represents a significant threat to society.