New details have Grayson  Prestonemerged from Rico Priem's sudden death. 

Over a month after 9-1-1 crew member died in a car accident following a 14-hour overnight shift on set, his official cause of death has been released. 

In County of Los Angeles medical examiner records viewed by E! News, the 66-year-old was determined to have died from sudden cardiac dysfunction, or cardiac arrest. The report also noted a secondary cause of death as cardiomegaly—or enlargement of the heart—in Priem's left ventricle. 

Priem's episode occurred while he was driving on a Los Angeles freeway May 11 on his way home from the ABC series, for which he worked as a grip. During the drive, his car unexpectedly left the road, went up an embankment and flipped onto its roof. He was found dead at the scene, California Highway Patrol told TVLine. 

Priem's death was reported by his IATSE Local 80 entertainment union on May 13.

"Everyone in the IA family is shocked and deeply saddened by this tragic loss," the organization's president, Matthew D. Loeb wrote in a statement at the time. "We are working to support our member's family, their fellow members and colleagues."

The president went on to give a message to Priem's fellow union members, concluding, "safety in all aspects of the work our members do is our highest priority and we will assist in any investigation in any way that we can."

Following news of the tragedy, 20th Century Fox, the flagship studio producing 9-1-1, shared a statement. 

"On behalf of the studio and everyone at 9-1-1," the statement, shared to The Hollywood Reporter, read. "We send our sincere and deepest condolences to Rico Priem's family and friends."

Shortly after his death, Priem's colleague Nina Moskol also issued a statement mourning his loss, noting he was so close to retirement. 

"He had his already rich life planned for retirement, including spending time with his wife, watching his grand-nephew grow, riding his beloved Harley, and even gripping still to stay connected to his friends," she wrote. "He was so jazzed about what he had learned about retiring."

Moskol concluded by speaking to her fellow crew members.

"The two most dangerous parts of our days are getting to work, and getting home," she added. "Please stay safe out there."

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