Authorities are searching for a paramedic-firefighter whose car was found in a parking lot in the Shenandoah National Park.

Thirty-one-year-old Nicole Mittendorff, of Woodbridge, Virginia, was reported missing Friday when she didn't show up for her job with Fairfax County Fire and Rescue. Family members say she is an avid runner and tri-athlete who might have been in the park to use a running trial.

She last had contact by text message with her family on Wednesday.

Police searched by ground and air Saturday and Sunday. Virginia State Police spokeswoman Corrine Geller says the search is concentrated around White Oak Canyon Trail, where Mittendorff's car was found. She says there is no evidence to indicate foul play.