Peter Grant is a character on DEXTER. He was the boyfrined of Holly Benson, one of the attempted victims of the Doomsday Killers, who was implied to be Grant's secretary. While Dexter was looking for Holly on the hunch that he might lead her to Travis Marshall, Dexter discovered her relationship with Grant and went to his house. There, Dexter was met with Grant's daughter who revealed the nature of Holly and Grant's relationship and who stated that Grant was currently in Spain or Portugal, with no certainty. She tells Dexter about Grant's yacht, the Ricochet Rabbit, which acted as Grant's "fuck pad".
Meanwhile, Holly, who had been given access to the boat while Grant was away, is cornered on the boat by Travis and two of his followers before being brutally murdered by them. Dexter, after posing as Grant on the phone to get to boat's location, later arrives at the Ricochet Rabbit where he finds Travis' follower, Steve Dorsey, preparing the Wormwood attack. Dexter kills Steve and finds Holly's corpse.
The episode in which Peter Grant is mentioned, Episode 610: Ricochet Rabbit, is named after Grant's yacht.