(Vancouver, WA)  --  Police say they've made an arrest in connection to a 25-year-old cold-case murder in Vancouver.  Police arrested 57-year-old Richard Knapp of Fairview yesterday and booked him into the Clark County jail on a charge of first-degree murder.  Police say investigators used DNA evidence to tie Knapp to the murder of Audrey Hoellein.  She was found dead inside her Vancouver apartment in July of 1994.  Police believe she was raped before she was murdered.