I think the article saying he was arrested in Seattle is incorrect. The following excerpt is from an appellate court opinion dealing with Alcala's case:
www.courtinfo.ca.gov/opinions/archive/S150806.PDF
(This excerpt is on Page 5 of a 32-page document.)
Excerpt:
When petitioner visited his girlfriend, Elizabeth Kelleher, in Long Beach on June 22, his hair was long and curly. On June 23, the composite sketch was distributed throughout the area; on that same day, petitioner straightened his hair with the aid of a chemical product. On June 26, he cut his hair.
On July 8, he told Kelleher he had decided to leave Southern California for Dallas, Texas, where he planned to establish a photography business. Kelleher accompanied defendant to the Monterey Park residence he shared with his mother to help him pack for the trip.
On July 11, defendant rented a storage locker in Seattle, Washington.
When he returned to California three days later, he did not mention to anyone that he had been to Seattle,
and instead told Kelleher he had been to Dallas. On July 23, defendant told Kelleher he would leave for Dallas on the following day and he told another acquaintance he would leave for Chicago. (Alcala II, supra, 4 Cal.4th at p. 760.)
Petitioner was arrested on July 24, however, and a search warrant was served on the home he shared with his mother. The police impounded a Datsun F10 parked at the residence and registered to petitioner, inside of which the officers found camera equipment and a briefcase containing a set of keys. Inside the home, officers seized sets of Kane Kut kitchen knives and observed a receipt for a storage locker located in Seattle, Washington. One of the officers copied the information on the receipt but did not seize
it. Officers returned the next day to retrieve the receipt, but it was gone.3(Alcala II, supra, 4 Cal.4th at pp. 756-761.)