Commander Eric Drever with the Tukwila Police Department said two people were arguing inside a room at the Riverside Residences when one of the men pulled out a knife and threatened the other.
The victim left the room and called police. When officers arrived, they saw smoke coming from the room and realized it was on fire. Fire crews arrived moments later and extinguished the fire.
"Police were able to quickly catch up with the suspect and apprehend him," Drever said. "Right now we're investigating with both fire and police investigators the cause of the fire, but we do believe it's a result of the altercation and we're investigating it as a potential arson."
Roughly 100 people were evacuated from the hotel, and many were taken to the Tukwila Community Center. It's unclear how much damage was done and when the hotel will reopen.