Police Say DNA LinksBouncer to Slain Student
Police Comr Raymond W Kelly says DNA evidence shows conclusively that blood found on plastic ties used to bind Imette St Guillen, 24-year-old graduate student who was sexually assaulted, strangled and dumped in Brooklyn marshland on Feb 25, belongs to Darryl Littlejohn, bouncer at Manhattan club where she was last seen alive; says evidence against Littlejohn, who is being held at Rikers Island on parole-violation charge, will be presented to grand jury that could hand up formal indictment within days; photos (L)

