The man who police discovered had built a secret, underground room in his backyard has been formally indicted by a Maricopa County grand jury and, as improbable as it may seem, new details about the case have once again made it even weirder than we originally thought.

William Willis, 45, was indicted on 10 counts of sexual exploitation of a minor after police discovered -- among other things -- a treasure chest of kiddy-porn at his house in Peoria.

They also discovered a tunnel in the house leading to a secret, underground room.

Police say the room was yet to become operational, but there's no shortage of speculation as to how Willis planned to put it to use. Our guess, based on some of the other goodies found in the house: sex dungeon.

Aside from the sex toys, kiddy-porn, and what police refereed to as "cross-dressing clothing," scattered throughout the house, Maricopa County Attorney Rick Romley mentioned a few additional items found in Willis' possession.

According to Romley, police found women's and girl's underwear that were apparently stolen.

Alleged panty raids aside, Romley says cops also found "inspirational posters of themes of engaging in sexual exploitation of a minor."

Check out more from the weird world of William Willis here.