Two Puyallup men arrested and charged with attacking all four substations. Expressed motive: cover for a burglary.
https://www.thenewstribune.com/news/local/article270620242.html
According to the criminal complaint filed with the court late Saturday and unsealed Tuesday, the two men were identified as possible suspects through the analysis of cell phone records. At one of the substations, Tacoma Power captured images of one suspect and the image of a pickup that appeared to be connected with the attack. A similar truck was connected to the defendants. When law enforcement served a search warrant on the home of the suspects, they recovered distinctive clothing pictured in the surveillance photos. Agents also seized two short-barreled firearms that had not been registered as required by law. One of the firearms was equipped with a make-shift silencer.
According to charging papers, Greenwood told law enforcement officers that he and Crahan planned the power disruptions to aid a burglary. After the attacks on substations in Graham and South Hill, they broke into a local business affected by the power outage and robbed the cash register.