A Tasmanian devil at a US zoo has had its skull crushed by a block of asphalt.
Police don't know if a member of the public or a zoo employee was responsible.
Jasper was one of four Tasmanian devils shipped from Australia to the Albuquerque Bio Park Zoo in New Mexico last December.
It appeared he did not die instantly, with evidence from an examination by the zoo's head veterinarian Ralph Zimmerman suggesting the injured devil crawled to a log in the enclosure before dying.
"The first suspicion of how the devil died was that it was possibly killed by another devil," the police report states.
"After the necropsy was completed and veterinarian Zimmerman found a small piece of the devil's skull fractured, staff went back into the enclosure."
A chunk of asphalt 10cm thick and the size of a dessert plate was located.
It appears the killer threw it at Jasper.
The devil's body was found on Wednesday morning, and zoo staff and visitors are the focus of the investigation.
Surveillance cameras are located on the zoo's walkways, but not on the enclosure.
About 4.30pm on Tuesday two young boys and an adult male can be seen on footage walking away from the enclosure area.
The zoo is one of only two in the US with Tasmanian devils and hopes to breed them.
"It looks like there was malicious intent and essentially our poor Tasmanian devil was killed, intentionally, by what seems to be blunt force trauma to the head," Albuquerque mayor chief-of-staff Gilbert Montano told TV station KRQE.
