What accounts for the sharp increase in the number of officer-involved shootings in Phoenix last year? A lack of mental health resources, according to a report released by the National Police Foundation on Friday. The report, which was commissioned by the city of Phoenix as a response to last year’s spike in incidences of officer-involved shootings, points to a number of underlying causes for the uptick. That police officers are fielding a growing number of 911 calls involving people with mental health issues is one of them.

Phoenix police officers who were interviewed for the study said they felt unprepared to respond to these kind of situations. Phoenix Police Chief Jeri Williams added that law enforcement officers shouldn’t be the first (or only) line of help available to people who are experiencing a mental health crisis and that many of the calls her department receives could be rerouted to alternative resources.