How can I research old criminial history records...probably in the 1920's in Oregon or Washington?

Our staff suggests you contact the National Archives in Seattle as they would hold the records for Oregon and Washington. They'll need to know the name, the court in which they were prosecuted, and ideally the docket number or  judgement number (for Oregon). Territorial court records are at the state archives.  You can contact them at seattle.archives@nara.gov with the information you have.

Another tip - if the crime could have been tried at a lower court, it may also be worthwhile for the researcher to look at what the Oregon and Washington state archives have with regards to court and jail records.