A fourth bighorn sheep released into the Santa Catalina Mountains on Nov. 18 has died, killed by a mountain lion, according to a new report from the state wildlife agency.

The Arizona Game and Fish Department had previously reported the deaths of three of the 31 desert bighorn sheep that had been released. The department is attempting to restore a population of bighorns in the Catalinas that died out in the 1990s.

The new report by the agency, which will begin providing regular updates for the project of reintroducing the bighorns back into the mountains north of Tucson, shows that on Dec. 9, an adult ewe was found dead, killed by a mountain lion. The mountain lion could not be found.

The previously reported deaths include two sheep killed by mountain lions, which were then tracked and killed by agency personnel. The deaths and mountain lion killings have angered many people who are calling for the agency to end the bighorn reintroduction program.

One of those bighorns killed was pregnant, Friday’s report states.

The first death, an adult ram found Nov. 27, was likely caused by a condition called “capture myopathy,” the report said. Capture myopathy is associated with the build-up of lactic acid in muscle tissue that can lead to heart failure. That condition can last in an animal for several weeks after capture and release, the report states.

The report did say game managers are optimistic to see that many of the released sheep are moving into more appropriate habitat that will help the population survive.

They said the sheep when initially released headed for higher elevations but remained temporarily in habitat that is considered dangerous for survival — areas with thick vegetation where predators can hide. Sheep are better protected from predators if they live in areas that afford them clear views.

Three of the deaths occurred in what game officials described as poor habitat — areas with dense vegetation. The fourth death was in a habitat described as fair, the report said.

Most of the released sheep are outfitted with GPS monitors that allows their locations to be tracked by Game and Fish.