Vel
Vel was a member of the terrorist group called Open Sky who resisted the Akritiri regime.
In 2373, he bombed the Laktivia recreational facility, killing 47 people. However, two Humans, Harry Kim and Tom Paris, that were visiting from USS Voyager were falsely blamed for it, and sentenced to prison.
When Captain Janeway discovered that the bomb was manufactured on his freighter, she detained him. When Janeway informed ambassador Liria of the new evidence, Liria nevertheless refused to release the crew members. At first Vel was uncooperative with Janeway when she asked for the location of the Akritirian maximum security detention facility. However in order to save his sister Piri from prison, Vel led Voyager to the prison where Paris and Kim were held; Janeway then let Vel and his sister go without informing Akritiri authorities. (VOY: "The Chute")