A Federation bureau that investigates incidents of time travel and enforces the regulations governing it.
The Department of Temporal Investigations is a Federation bureau tasked with examining every case of time travel and making sure the timeline has not been disturbed. Its agents are known for their dry, procedural manner and their deep dislike of temporal irregularities.
In Trials and Tribble-ations, agents Dulmer and Lucsly question Benjamin Sisko about the Defiant's accidental journey back to the 23rd century. Their interview frames the episode, as Sisko recounts how his crew moved among the officers of James T. Kirk's Enterprise without changing history.