The sister of one of the New Mexico convicts who escaped from a prison transport van last week and spurred a dayslong manhunt was arrested Thursday.

New Mexico State Police agents served the arrested warrant for Olivia Cruz, 38, at the Sandoval County jail, where she was being held on unrelated charges. She was arrested on the separate charges after authorities questioned her last week in the wake of the escape.

Cruz is accused of concealing and sheltering her brother, Joseph Cruz, and fellow convict Lionel Clah at a friend's apartment in Albuquerque. The convicts had found their way to the city after slipping out of their shackles and fleeing the transport van in a remote part of southeastern New Mexico.

Police arrested two other women Wednesday and charged them with aiding and harboring the convicts.

New Mexico State Police Chief Pete Kassetas promised last week that anyone who helped Cruz and Clah elude capture would be arrested and charged.

Despite the arrests, authorities have yet to say how Cruz and Clah were able to escape without two guards noticing.

Investigators believe the men picked their handcuffs, but it's still not known how they broke free from their leg irons, ditched their white prison jumpsuits and changed clothes, and got a ride north to Albuquerque, a roughly three-hour drive.

Authorities believe the escape, which has raised concerns about security within the state's financially strapped corrections system, happened during a fuel stop in the small community of Artesia. The two guards had already put in significant overtime by the time they stopped for gas that night.

Cruz, 32, had been serving a life sentence for a first-degree murder conviction since 2007 for killing a man over drugs in northern New Mexico. Clah, 29, was serving time for armed robbery and other crimes.

The other women arrested Wednesday were identified as Michelle Abeyta, 40, of Albuquerque, and Patricia Petrushkin, 51, of Humble, Texas. Petrushkin was taken into custody at a Houston airport and is awaiting extradition.

It was not immediately unclear if either woman had a lawyer.

Abeyta allegedly turned in Clah after she allowed him to stay at her apartment. Petrushkin is accused of harboring Clah and Cruz in her Albuquerque hotel room and of giving them money and clothing.

Cruz was taken into custody in Albuquerque after a brief foot chase after two days on the run. Clah surrendered to police Saturday at an Albuquerque apartment.