ROCKSPRINGS, Texas (AP) — Investigators say a brother and sister have been charged with capital murder in the 1996 killing of their aunt during a South Texas robbery.

Edwards County jail records show 37-year-old George Torres Jr. and 40-year-old Angelica Maria Torres were being held without bond Sunday.

KSAT-TV reports 35-year-old Patricia Paz of Rocksprings was stabbed to death in February 1996 during a robbery. Sheriff's Capt. Darrell Volkmann says the victim was mentally challenged and the alleged motive for the attack was to get money to buy drugs.

Jail records do not list an attorney to speak for the siblings, who were arrested Friday at a home in Rocksprings, about 125 miles northwest of San Antonio.

Authorities didn't immediately say why investigators last July took another look at the unsolved killing.