Livermore police and FBI agents went to the home of Christopher Kalish, 26, at 5525 Crestmont Ave. last Wednesday after receiving reports that he was involved in the distribution of child porn, police said.
A search of Kalish's computer yielded images of children engaged in lewd acts and evidence that those images had distributed on the Internet, according to police.
Kalish was arrested on suspicion of distribution of child pornography and booked into the Santa Rita Jail.
Police said Kalish has volunteered with the Livermore Area Recreation and Park District, and in that role has assisted with teaching rock climbing to kids.
There is no indication that Kalish molested his students or other children, police said.
Investigators are asking parents whose kids may have been in contact with Kalish to ask their children about their interactions with him. Anyone with knowledge of any crime involving Kalish is asked to call Livermore police Lt. Ava Garavatti at (925) 371-4730.