Tolen Ren was a Banean scientist whose murder was pinned on Tom Paris in Ex Post Facto.
Tolen Ren was an engineering physicist on the Banean homeworld who helped Tom Paris and Harry Kim with damaged equipment and invited them to his home. He was considerably older than his wife Lidell, and his work had military value in the Banean war against the Numiri.
In Ex Post Facto, Ren was stabbed to death in his living room, and Paris was convicted of the crime. As punishment, Paris was forced to relive Ren's final moments every fourteen hours through an implanted memory. Tuvok proved that the memory had been altered and that Ren's real killer was the Banean doctor who was Lidell's lover.