A search for a family of four in the rugged Black Hills area of South Dakota ended Friday after authorities found a stolen truck that they believe the family used to return to their home state of Nebraska.

Matthew and Rowena Schade and their children, ages 8 and 11, have not been seen since March 20, when a Knox County deputy sheriff interviewed them in their Creighton home about allegations of abuse. Matthew Schade, 26, has attended a survival camp in Black Hills for several years through his church.

Knox County Sheriff Jim Janecek declined to comment Friday on whether he believed Rowena Schade and the children were with Matthew Schade willingly. He also declined to discuss the search strategy in Nebraska.

"The best thing they can do is contact us and end this before we have more problems arise," Janecek said.

The deputy who interviewed the family "made an offer of help and counseling. No arrests were made and no injuries were observed," Janecek said. The Schades are believed to have left Creighton the same day.

The family's car had been found Tuesday about 400 miles from Creighton, near Silver City, S.D. The vehicle found Friday in Antelope County, next to Knox County in northeastern Nebraska, belongs to the Silver City volunteer fire department and typically is used in fighting brush fires.

As many as 25 people searched for the Schades in the Black Hills, but the search was scaled back Thursday after Matthew Schade called his father and said the family was OK and wanted to be left alone. The search stopped at nightfall because it became too difficult to navigate the loose rock and melting snow at nearly 5,000 feet in elevation.

Authorities had speculated that Schades could have ridden out an expected snowstorm by taking shelter in one of the many abandoned mining tunnels through the area and hunt for their food.

Matthew and Rowena Schade are on probation in Nebraska for burglary. An arrest warrant was issued for Matthew after he failed to notify a probation officer of his whereabouts.

Investigators said the Schades, who spent their honeymoon in the Black Hills, had talked about relocating. It also appeared they left the house in a hurry with more than $1,000 worth of what authorities described as "camping survival-type gear" the Schades had recently purchased.

Matthew Schade attended a survival camp in the search area through his church and "expressed he would like to live like a hermit in the mountains," Maj. Brian Mueller of the Pennington County Sheriff's Office told The Associated Press.