Salemburg, N.C. — Crews searched by land and air Thursday for a Sampson County woman and her 13-year-old son, who have been missing for three days.

Relatives, meanwhile, are thinking the worst.

"(I'm afraid) that she's somewhere lying dead, both of them," said Mary Esther Avellaneda's brother, John Anthony Garcia.

Authorities said Thursday they are treating the disappearance as a missing persons case because they have no evidence to indicate any wrongdoing.

"If there was any potential for foul play, we wanted to go ahead and do a search," said Sampson County sheriff's Capt. Eric Pope.

Family members last saw Avellaneda, 38, and her son, Jose Andres Avellaneda, leave their home around 9 p.m. Sunday with her estranged husband, Jose Cruz Avellaneda.

About 20 minutes later, he returned home alone and hasn't been seen since, they said. They did receive a phone call from him Wednesday morning.

"Mr. Avellaneda's not providing the family with any information," Martin said. "We attempted to trace that phone call, but have been unsuccessful."

Family members also say there is a history of domestic violence between the couple and that it is not in Mary Avellaneda's character to stay gone without letting someone know.

"Wherever she's at, she calls home, or calls me or my brother or somebody," Garcia said.

Authorities said Jose Cruz Avellaneda was last seen driving a 1995 four-door white Chevrolet Lumina with North Carolina license plate XZX-8054.

Anyone who might have information about any of the missing family members' whereabouts can call the Sampson County Sheriff's Office at 910-592-4141.