The Pima County Sheriffs Department responded to a shooting report near East Lamb Drive and North Oracle Road on Tuesday at 2:20 p.m.
They found 47-year-old James McLaughlin injured from a gunshot.
Life-saving measures were administered until the Golder Ranch Fire Department took over, transporting McLaughlin to a local hospital with serious, non-life-threatening injuries.
The suspect, 46-year-old Clifford Bretthauer, ran away from the scene during the assault.
According to the PCSD, the victim was assaulted while cleaning a homeless encampment on his property.
The victim defended himself by firing his weapon, injuring McLaughlin.
This search for Bretthauer continues as the investigation unfolds.
Anyone with information is asked to contact 911 or 88-CRIME.