COLUMBIA (AP) – Authorities stepped up the search Wednesday for a teenage girl who went missing last weekend after she drove her car from a friend’s house and said she was headed home.

A dozen game wardens and scores of volunteers joined in the search for Crystal Higgins, 17, of Columbia, who was last seen Saturday night.

Police and friends described Higgins as stable and responsible, saying that she works two jobs and has a paycheck waiting for her at one employer.

“This isn’t like her,” said Janis Lesbines, a friend who housed Higgins last fall and winter. “Something has gone terribly wrong.”

Higgins’ cell phone was used seven times to call two friends between 1 and 1:30 Sunday morning, police said, but there have been no phone signals since then. The calls were determined to originate from within a 15-mile radius of the Milbridge cellular tower, according to Washington County Sheriff Joseph Tibbetts.

The aerial search for Higgins’ gold 1997 Chevrolet Cavalier covered Jonesport, Columbia and Harrington.

“If we find her car, we hope we will find her with it,” said state police Lt. Peter Stewart, who was overseeing the search.

The ground search is taking wardens and other volunteers down dozens of dirt and side roads.

Higgins does not live with her family. A senior at Narraguagus High School, she was legally emancipated from her parents just before she turned 16. Her father is incarcerated at Down East Correctional Facility in Machiasport.

Since April she has been living with Debra Skeate, the mother of Tara Skeate, her best friend since fourth grade. Before that, Higgins had been staying since October with Janis Lesbine’s family, also in Columbia.