A humourless investigator from the Federation Department of Temporal Investigations who, with his partner Lucsly, questions Captain Sisko about the Defiant's unplanned journey back to Deep Space Station K-7 in the twenty-third century.
Dulmer is an agent of the Department of Temporal Investigations, the Federation body that reviews every incident of time travel involving Starfleet. He appears in Trials and Tribble-ations, played by Jack Blessing.
In 2373 he and his partner Lucsly arrive on Deep Space 9 to take Sisko's statement after the Orb of Time carries the Defiant back to 2268, where Arne Darvin tries to kill James Kirk with a bomb hidden in a tribble. Dulmer is the slightly less exact of the pair, and is corrected by Lucsly whenever he rounds off a date.
Both men admit to a deep dislike of predestination paradoxes and of Kirk, whose file of temporal violations is the largest the department holds. Dulmer's name is an anagram of Mulder, a nod to The X-Files.