Jasper the devil died when the asphalt crushed his head at the Albuquerque Bio Park Zoo, New Mexico.

Police so far believe Jasper may have been hit by the thrown piece of asphalt on Tuesday afternoon and retreated to a log in his enclosure, where he died. 

His body was discovered Wednesday morning, US time and an autopsy found the devil's skull had been fractured.

The police report stated: ``After the necropsy was completed and veterinarian (Ralph) Zimmerman found a small piece of the devil’s skull fractured, staff went back into the enclosure.''

The report went onto say that a 10cm thick piece of asphalt, the size of a dessert plate, was located inside the enclosure.

Police said they have footage of a male adult and two young boys walking away from the enclosure.

The devil was one of four sent from the Healesville Sanctuary in Victoria, to the zoo in December 2013, as part of the Save the Tasmanian Devil ambassador program.

According to the organisation's website, the devils arrived at the zoo in late December and went on display in their exhibit at the end of that month.

The zoo is the second in the US to receive devils as part of the ambassador program, with the San Diego Zoo Global receiving them in October 2013.

Three zoos in New Zealand have also accepted devils.

The program was to be assessed before being expanded to include other North American, European and Asian zoos.