(Portland, OR)  --  Police say a man arrested in connection to a massive four-alarm fire that destroyed two buildings in northeast Portland could be responsible for other fires as well.  The Portland Police Bureau says Allen Singerhouse may have started more fires in the Portland area over the past couple of years.  They're looking into whether he was responsible for fires in the Southeast 101st Avenue and Southeast Foster Road area in particular.  Police arrested Singerhouse late last week for the fire that started as two small fires near Northeast 82nd Avenue on August 26th.  Investigators say Singerhouse has admitted to starting the blaze.