The actor, who began his career as a child actor on Little Giants and Star Trek, died on Jan. 1 at the age of 33.
On Monday, Steuer’s cause of death was revealed with The Blast reporting he died from a gunshot wound to the head.
The Portland Police Bureau’s spokesman Sgt. Chris Burley told People they suspected no foul play in Steuer’s death.
Steuer’s death was announced by his band, P.R.O.B.L.E.M.S., on Facebook in January.