Multiple calls came in around 12:45 a.m. Sunday from a “sizable trailer park community” regarding shots fired, Tucson Police told CNN.
Police said officers were on the scene and found three people dead around the trailer where the shooting took place “near the northwest area of the park”.
According to Tucson Police, a fourth person was taken to a hospital, where they later died.
“This was not a random act and could have started as a confrontation between two groups,” police told CNN.
Authorities are working to identify the victim and suspect.