MITCHELL, S.D. (AP) - Blame is being spread around for the disappearance of an Omaha prisoner who simply walked away from a van full of prisoners as it crossed through South Dakota.

Oscar Antonio Herrera-Menjivar is still on the loose nearly three months after his July disappearance. He was one of 13 prisoners aboard a van operated by the private transport company Inmate Services Corp. of Arkansas.

The Mitchell Daily Republic reports (http://bit.ly/RaEkee ) the van's driver stopped to get a drink, and the secondary guard was asleep, allowing the prisoner to grab a bag of clothes and walk away.

The newspaper reports that the incident underscores problems with private companies moving prisoners. But while law enforcement blames Inmate Services, the company places blame on shoddy response time from the McCook County Sheriff's Office.