ALPINE, Texas (AP) — Volunteers have joined law officers in the search for a Sul Ross State University student who's been missing since last week.

Alpine police on Tuesday announced a $17,500 reward for information leading to the whereabouts or safe return of 22-year-old Zuzu Verk. The reward was initially $7,500.

A police statement says Verk has been missing since Oct. 12 and could be in danger. Police didn't elaborate.

Law enforcement officers in aircraft and volunteers on foot searched for Verk in the area near Alpine, about 210 miles southeast of El Paso.

Verk, in a posting on the university's Borderlands Research Institute site, said she's from Fort Worth and formerly attended the University of North Texas. Verk says she decided to study conservation biology and worked last summer as an undergraduate researcher.