A warrant has been issued for a violent sexual predator whose whereabouts are unknown. Howard Edward Martin’s last known address was in Post Falls. The 30-year-old was convicted in Washington of raping his sister at knifepoint and also of attacking his female counselor during sex offender therapy, according to a press release. Martin was also convicted in Washington of failing to register as a sex offender. He was classified as a violent sexual predator by authorities in Idaho and Washington and is considered at a high risk to reoffend, according to a press release here.