'Suggest' that he reads the section on stealing on the job in Attitude before the next session. If he continues stealing, have some of those things burn his contacts. Soon, he's going to get a crap rep, which will affect his team rep as well, which will affect the jobs they get called in on. And he'll also have contacts who will stop moving stuff for him, or who may just stop talking to him altogether. Just remember, it doesn't matter what the actual item stolen was. Sometimes, just the fact that an item was stolen from X place at Y time when Z thing happened is enough for the people who may want to dish a bit of payback to connect the dots.
In general, stealing things that aren't part of the job is a bad idea, unless the thefts are a cover to distract people from the actual job (stealing a bunch of stuff from the warehouse to disguise the fact that you switched the shipping labels on a few containers to redirect a few shipments to the client, for instance).