How does Letch get ahold of Serenity Jones?

Letch takes Blaze’s private client telephone book and decodes the number under S. The number looked suspicious, because it said pet shop, but Blaze did not own a pet. When one of the numbers took longer to ring, he knows something smells fishy, as it is a call forwarding location. He learns from connections at the phone company and Air Touch that it is a cell phone belonging to Serenity.