Lieutenant Hevelin was assigned to the Enterprise's Security division. He was described as older and brawny with a "crusty" attitude.
In 2269, Hevelin was a member of the first landing party that visited the planet Anomaly, traveling with Captain James T. Kirk in the first shuttle along with Sharon Follett, Octavio Hernandez and security officers Bounds and Mark Moore.
Later, Hevelin went with Kirk and others to get water samples. On the way back, Hevelin was eaten by a carnivorous flowering vine plant while saving Alan Huff. Vines from one of the plants had grabbed Huff's ankles. Hevelin freed him with a machete, then got ensnared, dragged into the plant and partially digested. He was buried on Anomaly. (TOS novel: Planet of Judgment)
- Hevelin was identified as a lieutenant while talking to Mark Moore.