SALEM, OREGON—Jack Lee Harelson, who was convicted of looting ancient graves in the Nevada desert and of an attempted murder-for-hire, has died in an Oregon prison of natural causes at the age of 72. In 1995, police found the headless mummies of two children buried in Harelson’s garden. Their remains had been plundered from Elephant Mountain Cave in the Black Rock Desert, along with the baskets the children had been buried in and some 2,000 other artifacts. The children’s skulls were later recovered in a separate investigation. In 2005, Harelson was convicted for trying to hire someone to kill the man he blamed for his looting conviction.