Chain Letter (Chain Letter, #1)

And alternate cover edition can be found here.

When Alison first read the chain letter signed "Your Caretaker," she thought it was some terrible sick joke. Someone, somewhere knew about that awful night when she and six other friends committed an unthinkable crime in the desolate California desert. And now that person was determined to make them pay for it.

One by one, the chain letter was coming to each of them ... demanding dangerous, impossible deeds... threatening violence if the demands were not met. No one out of the seven wanted to believe that this nightmare was really happening to them. Until the accidents started happening -- and the dying...