Two inmates and three other people tried to extort $10,000 from the parents of a college student whose mutilated body later was found in a mass grave in Mexico, authorities said.

The Galveston County Jail inmates were arrested Thursday and accused of using jail telephones to call Mark Kilroy's parents in nearby Santa Fe, Texas, where they were awaiting word on the whereabouts of their son, who vanished in Matamoros, Mexico.Santa Fe Police Chief Mike Barry said a caller vowed to cut off the missing student's fingers and mail them to the family if police arrested or followed people to whom the Kilroys delivered ransom money.

The body of the University of Texas junior was found in a shallow grave near Matamoros, Mexico, on April 11, one week after the extortion attempt allegedly began. The body had been mutilated in a human sacrifice ritual by Mexican drug smugglers, police said.

Police said the inmates and the other three people were not believed to be involved with the cult but had heard Kilroy was missing and were trying to cash in on it. All five have been charged with attempted robbery and ordered held in lieu of $20,000 bail.

Kilroy's mother apparently tried to pay the initial $2,000 the group sought, but the payoff was not made, Barry said.