Visitors at the Beverly Glen Deli in Los Angeles today were surprised when an FBI agent walked in and handcuffed a patron eating lunch there. Turns out it was White Collar star Tim DeKay in an FBI uniform fake arresting The Shield and The Chicago Code creator Shawn Ryan assisted by the show’s writers PA Chris Masi, also in FBI gear. It was part of an ongoing Twitter war between Ryan and White Collar creator Jeff Eastin. The two started trading insults via the micro-blogging service early this year, with the feud moving to another level on Super Bowl Sunday when Ryan broke into Eastin’s office and took a picture of himself at Eastin’s desk (photo on left). During White Collar‘s panel at the PaleyFest last night, Eastin alluded to a big practical joke against Ryan coming in retaliation for the break-in. As for today’s arrest, “most of the restaurant thought it was real,” one witness said. “It was funny.” According to onlookers, Ryan was having lunch with David Madden, who probably served as bait as he is president of Fox TV Studios, the company that produced The Shield and is also producing White Collar. The writers for the USA series greeted Ryan outside the restaurant, and they also brought along TMZ cameras to commemorate the event. BTW, the Twitter revelry between Ryan and Eastin is for charity. Here is cell phone video of the incident taken by a visitor.