A station agent reported a male was at the booth reporting that someone was trying to kill them and talking gibberish. An officer responded to conduct a welfare check. The officer determined the male was able to care and did not require medical assistance. A records/warrant check showed the male was out of compliance (290 PC registrant) and was detained. The officer contacted Monterey County to confirm the male was out of compliance and was placed under arrest for being out of compliance. The male was booked at the Redwood City Jail. A sergeant approved the arrest.