The Mysterious Experience of a Cell Phone Caller

If this experience were to have a natural explanation it would involve a cell phone that someone had in the car and for some reason the cell phone activated and placed a call without anyone realizing it. In which case this would fall into a category in parapsychology known as after-death communication or ADC. People do report receiving phone calls, voicemails and now even text messages from the deceased. Sometimes the messages are in the dead person's own voice. Do you have any ideas as to what this could be?