(Portland, OR)  --  A fire broke out in a recently vacated apartment in southeast Portland early Sunday morning.  The apartments are located near Southeast 118th and Holgate.  Firefighters quickly put out the fire before it could spread to other units.  None of the other residents was displaced.  Police detained and released one person.  Fire investigators believe the fire was intentionally set.  They're asking anyone with information about how the fire was started to contact them.