An Arizona middle school principal resigned amid fallout from failing to notify police of a threat to the school.

In a letter posted on the district site, the Globe Unified School District said the administrator at High Desert Middle School learned of a threat last week that included a map and plan for a homemade bomb and handguns, but did not alert authorities.

A parent told the Globe Police Department of the situation, and since then, four students have been charged with felonies, as well as being suspended from school. The former administrator is also accused of endangerment as the police investigation continues.

"This incident has brought to light the fact that we need to make sure that staff does not become complacent," the district said in the statement, "and that all of our safety protocols are updated."

The district also said that it has requested a permanent school resource officer, but Globe's funding constraints have prevented the allotment of one.