When Nate's apartment was burglarlized
Who else thinks that James,Nate's boyfriend,arranged the burglary? Remember when James was texting and making calls during the dinner Margaret gave for them? He soon insisted they go to a club where his old boyfriend was a DJ. At some point Nate said he had lost his keys and James said "Oh, they'll turn up". James did his best to keep Nate there as long as he could.
I think the only reason that Margaret was blamed was due to bad timing. She just happened to go in and clean his apartment that same evening. James probably took Nate's keys and handed them off to a friend to go and steal Nate's stuff.
I think James spotted Nate as an easy mark right off the bat.