Looks like Gibbs and the rest of the NCIS team are going to need even more help than they thought to nab the Port-to-Port killer.Dawson's Creek star Kerr Smith has booked a season-ending, two-episode arc on the CBS crime drama, TVGuide.com has learned exclusively. Smith will play Lt. Jonas Cobb, a confident former military man.Sounds like standard fare on NCIS, right? Not so fast. "Lt. Cobb's unique talents and training will play a key role in helping the team figure out the identity of the Port-to-Port Killer," executive producer Gary Glasberg tells us.Smith's casting follows that of NUMB3RS star Alimi Ballard and Matthew Willig, both of whom play NCIS agents reporting to E.J. Barrett (Sarah Jane Morris). Ballard and Willig's characters debut on Tuesday, as Barrett's team is officially given the lead in the Port-to-Port Killer case.E-Ring, Justice, and most recently, Life Unexpected. He also held a recurring role on ABC's Eli Stone and memorably played the "333 Caller" on CSI: NY.NCIS airs Tuesdays at 8/7c on CBS. Smith will appear in the May 10 episode as well as the May 17 season finale.