(Portland, OR)  --  Police say they've arrested a second suspect in connection to the shooting death of a 30-year-old man downtown.  Police arrested 18-year-old Avarihae K. Collins during a traffic stop.  He's accused along with 24-year-old Aaron D. Birt of shooting and killing Ellante Davone Williams at Southwest 4th Avenue and Stark Street in late January.  Police arrested Birt the night of the shooting.