Authorities say the homeowner was in his house and went to check on the property next his when the shooting occurred.
Fanning was arrested on suspicion of second-degree murder, but Dorsey will decide what, if any, charges to file.
The Olympian reports Bruce Fanning was arrested after reporting the incident. When he arrived next door he saw a screen window punched out and the door kicked in. Fanning told detectives he was afraid and thought the intruder was drunk.
Detectives say the homeowner exchanged words with the man then went back to his home, got a gun and returned and shot the intruder multiple times through the shower curtain.
Prosecutor Michael Dorsey said Tuesday that he anticipates a decision on charging Bruce Fanning, 59, by Wednesday afternoon and offered further details on the events that led up to the death of Nate Rosa, 31, a paraeducator from Bothell who worked with disabled children.
While not citing any specific evidence, local law enforcement said there is "more to the story". "Homeowner charged for shooting someone in his shower?"
"Lots of reactions to the arrest", the office wrote in an April 1 tweet.
Fanning left, got his handgun, and Spurling said he "reintroduced himself to the situation and shot".
Fanning's bail was set at $250,000.
'Rest in piece Nathaniel Rosa.
The intruder was killed, officials say.
Washington does not have a "castle doctrine", which is a law that exonerates homeowners for using deadly force against an intruder.
"Fanning first told the intruder to leave and the intruder aggressively responded with non-understandable verbal threats", reads the probable cause affidavit.
The Mason County Sheriff's Office responded to some of the concerns over Twitter, writing that people should wait until more information is released before making judgments.