Michael Vawter, the 40-year-old ex-Cub Scout leader accused of downloading child pornography onto his work computer, pleaded not guilty Thursday to the felony charge.

A judge also set Vawter's preliminary hearing time for 8:30 a.m. on July 22 at the Walnut Creek Superior Court where Thursday's hearing took place.

Vawter, who showed up with a private attorney, wore a grey suit and didn't say anything during his short arraignment. The prosecutor assigned to the case is Dana Filkowski, of the Family Violence Unit in the Contra Costa County District Attorney's Office.

San Ramon police arrested Vawter in March after a tipster alerted investigators that the one-time Scout leader allegedly stored 75 or more illicit pornographic videos on his work laptop.

Detectives, with help from Vawter's supervisor at CCI Financial in San Ramon, said they saw on his removable drive a clip depicting a masked man having sex with a girl who appeared to be a preteen.