There's a murder mystery of sorts ongoing in Yellowstone National Park, and the main suspects include wolves, hunters and Mother Nature.

The victims are the park's elk herd, which is declining at an alarming rate for an undetermined reason.

The park's elk population dropped from nearly 17,000 in 1995 to about 8,000, USA Today reported, noting 1995 was the year wolves were reintroduced into the 2.5-million-acre federal park that covers parts of Wyoming, Montana and Idaho.

Although the reintroduction of wolves to the park was expected to negatively impact the elk population, the decline is much greater than expected, biologist John Vucetich of the Michigan Technical University told USA Today.

Vucetich and park officials considered weather, hunting and wolves as factors in the elk decimation and decided weather and hunting was mostly to blame.

The park area has experienced seven years of drought and a severe winter in 1997, both of which claimed many elk.

But other experts disagree, believing grizzly and black bears are the culprits.

Copyright 2005 by United Press International