(Portland, OR)  --  Police say one person was arrested during dueling demonstrations outside the Justice Center.  The Portland Police Bureau says two groups of about two-dozen people each gathered at the building yesterday afternoon.  One of the groups was calling itself pro-police, with members carrying "Trump 2020" flags.  The other group called themselves antifascists and counterprotesters.  It's not yet clear what led to the arrest or which group the person arrested was in.