Wildlife managers are investigating the death of a Mexican gray wolf on tribal land in eastern Arizona.
The male wolf was found dead at the end of March on the Fort Apache reservation. The animal belonged to one of two packs known to frequent the area.
State and federal officials involved in the reintroduction effort say the cause of the wolf's death remains under investigation. It marks the second wolf death since the beginning of the year.
The reintroduction program has been hampered over the years by politics, illegal killings and other factors. Disputes over management of the predators also have spurred numerous legal actions by environmentalists and ranchers.
A survey in January showed there were at least 83 Mexican wolves in the wild in Arizona and New Mexico.