Sons of Anarchy star, John Paul Vasquez's cause of death remains a mystery, RadarOnline.com has exclusively learned.\n\nAccording to the Santa Clara Medical Examiner the results of how he died are "still pending."\n\n"A toxicology report is being conducted," a spokesperson for the medical examiner told Radar. "It could take anywhere from four to 12 weeks to determine the cause of death."\n\nVasquez, who was only 48 when he died, was found unconscious Monday night, September 24, at his father's home in San Jose, California.While his exact cause of death remains under investigation, earlier reports suggest he suffered a heart attack.\n\nHis death comes on the heels of the death of his Sons Of Anarchy costar, Alan O'Neill. O'Neill passed away at the age of 47 in June from "chronic ethanol (alcohol) overconsumption."\n\nVasquez's end marks the third death of a star from the dramatic biker gang TV show.\n\nOn September 26, 2012, Johnny Lewis, 28, who appeared on the first two seasons of the FX series, and his 81-year-old landlady Catherine Davis were found dead at her home.Officers from the Los Angeles Police Department found Lewis' body on the home's driveway. Davis was found dead inside the villa, which appeared to have been ransacked.\n\n.\n\nHis death was ruled accidental.\n\nWe pay for juicy info! Do you have a story for RadarOnline.com? Email us at email@example.com, or call us at (866) ON-RADAR (667-2327) any time, day or night.\n\nFor the biggest celebrity news stories of the day, controversies, crime, and other hot topics listen to our new podcast ‘All Rise’ below!