How To Report An Unregistered S.o.

My father did horrific things to my elder sister that I won’t go into detail on and spent 12 years in prison for it.

He got out a few years ago and I’ve recently done a background check on him and learned that he’s failed to register anywhere in the entirety of Washington state where we live, he’s also driving around in a $50k car, whereas the family he ruined has been homeless multiple times.

He is living his life happily and with zero repercussions because he apparently can just NOT register and no one noticed except for me.

I want him back in prison, and he’s thankfully made that very easy for me to do considering failing to register as an S.O. can garner 10 years in prison.

But I don’t know how to report him and get results.

I would like for someone to help me with this if they could.

I have found him on social media and now know what city he lives in.

I know reaching out to the U.S. Marshals office is a way, but I am getting confused by where I’m supposed to go on the website.