A thief stole a woman's cellphone while she was out for a morning jog Friday on a Wildwood Park trail in Thousand Oaks.

The woman said she heard footsteps behind her.

"She turned around to see a male with his face covered," Detective Tim Lohman of the Ventura County Sheriff's Department said. "He took her cellphone and he ran north, out of the park."

The jogger was not hurt. Authorities described the suspect as tall, in his 20s and wearing dark clothing.

Residents were concerned.

Holly Healy said she uses the park on a regular basis and doesn't see many joggers during the early morning hours.

"I would never go by myself," she said. "I would suggest that for anybody."

The thief reportedly took her cellphone, which he tossed before he disappeared.

Deputies searched with a helicopter and dogs throughout the morning, but found nothing.

Deputies encouraged runners to run in pairs when traversing on remote trails and to carry a cellphone for emergencies.