SACRAMENTO, Calif. (CN) — Two men accused of kidnapping U.S. Forest Service workers last month said nothing Monday as they sat before a federal magistrate judge in California’s capital. Authorities say Joseph “Charles” Henrichsen, 49, and his son, Phoenix Henrichsen, 23, held Forest Service employees hostage for several hours in the Shasta-Trinity National Forest. Joseph Henrichsen also faces up to 20 years on each assault with a deadly weapon charge and substantial fines. According to law enforcement, Joseph Henrichsen encountered two Forest Service employees conducting frog habitat surveys near Gumboot Lake Campground in the Shasta-Trinity National Forest on July 16. The older Henrichsen took one of the victims at some point, put her in a Forest Service Nissan and drove several miles.