Officers were dispatched to 1119 Briggs Ave. at about 2:20 a.m. on a report of an armed robbery.
When the officers arrived to the vacant lot they learned that the suspect, William Fisher, 40, had allegedly displayed a large knife and then demanded money and property from someone.
The victim complied and Fisher took off. An investigating officer learned that Fisher, a Santa Rosa resident, frequents the Homeless Services Center, located at 600 Morgan St.
At about 6:15 a.m., the officer went to the center and found Fisher. The suspect attempted to leave and allegedly struck the officer with his hands. The officer asked for emergency assistance. Help arrived and Fisher was taken into custody.
Two officers received minor injuries while they were trying to arrest Fisher. The suspect, who also was injured, was taken to a local hospital. He was treated and then booked at the Sonoma County jail.