Forty-four Mexican gray wolves have been illegally killed since 1998.

Another endangered Mexican gray wolf has been gunned down in southeastern Arizona, the 44th known illegal killing since the wolves were reintroduced in the region in 1998.

Although illegal killings rank as the leading cause of death for the most endangered wolf subspecies in the world, few people have ever been prosecuted for killing a Mexican wolf.

Wildlife officials confirmed in April that the young female – a member of the Hawks Nest Pack, which has a good reputation for avoiding cattle – died from a single gunshot wound, according to the Associated Press.

Defenders of Wildlife has contributed $10,000 to a reward fund of almost $60,000 for information leading to the conviction of the person or people responsible for the shooting.

With only some 58 Mexican wolves in the wild, it is crucial that the U.S. Fish and Wildlife Service release more wolves to keep the population from backsliding toward extinction.