An Alameda County firefighter made his first court appearance this week on federal charges of possession of child pornography, the Department of Justice announced.

Charles Johnathan Harris, 42, from Coulterville, was indicted on March 2. Harris is alleged to have possessed images of child pornography on his iPhone, including images of prepubescent children.

Federal authorities received a tip in the case from the National Center for Missing and Exploited Children, which allegedly uncovered uploaded child pornography over the social media platform Kik, which the defendant allegedly uploaded "even while present at fire stations in Alameda County," the prosecutors said.

Harris surrendered to federal authorities on Tuesday and was released on bond with the condition that his access to the internet be restricted.

His next court appearance will be on April 19.