(NEXSTAR) — A beloved bull elk well-known among Rocky Mountain National Park visitors and photographers for his distinctly large antlers has died, according to park rangers. While the elk’s death isn’t suspicious, his missing skull and antlers have sparked an investigation.

Park officials say the elk, commonly referred to as Kahuna, Bruno, or Big Thirds, is believed to have died of natural causes earlier this year. There had been reports that Kahuna was injured during the mating season last year, and was very underweight in February.

Now, rangers are trying to determine who illegally removed Kahuna’s skull and antler from his carcass.

Good Bull Outdoors, a husband and wife team that shares photos and videos of wildlife, including Kahuna, claimed to have found the elk dead in mid-March, saying they observed mountain lion and bird tracks around the carcass.

Kahuna’s skull and one antler – the other antler likely shed before his death – are believed to have been removed between March 20 and March 22.

“This elk’s remains should be allowed to return to the earth in Rocky Mountain National Park, where he brought much joy to thousands of park visitors over many years,” the park said in a release last week.

Anyone with information is asked to call Rocky Mountain National Park’s tip line at 970-586-1393 or contact them by e-mail by using this form. While you can remain anonymous through either of these messages, you can also submit information via the National Park Service’s Anonymous Tip Information form.

An elk and a mule deer were illegally killed in the park at Bandelier National Monument in November, Nexstar’s KRQE reports. Officials have not yet said if anyone has been arrested for these two incidents.

Poaching carries a penalty of up to six months in jail and $5,000 in fines.