Members of a missing Nebraska family are believed to be back in the state, authorities said Friday.

A truck suspected of being stolen in South Dakota and used by the Matthew and Rowena Schade family has been found abandoned in Antelope County in northeast Nebraska.

The discovery of the vehicle has led law enforcement agencies to end their search efforts for the family of four in the rugged Black Hills area of southwest South Dakota.

The search had been scaled back Thursday after Matthew Schade called his father and said the family was OK and wanted to be left alone. The family was last seen March 20 at its home in Creighton, Neb.

Creighton is in Knox County, which is adjacent and north of Antelope County.

Knox County Sheriff Jim Janecek declined to comment Friday on whether he believed Rowena Schade and the children were with Matthew Schade willingly.

Janecek 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 four members of the Schade family were interviewed March 20 by a Knox County deputy sheriff about allegations of abuse, according to statements from Nebraska and South Dakota law enforcement agencies.

The deputy "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 was found Tuesday about 400 miles away near Silver City, S.D.

The vehicle found Friday in Nebraska belongs to the Silver City volunteer fire department and typically is used in fighting brush fires.

Authorities searched Thursday for Matthew and Rowena Schade and their children, Devon, 11, and Sean, 8, near the Pactola Reservoir, which is 15 miles west of Rapid City.

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.

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.

For six straight years, 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.