Berel

From Memory Alpha, the free Star Trek reference.

Berel was a doctor in charge of a medical facility on Malcor III.

He treated a Malcorian named Rivas Jakara, who was in reality William T. Riker disguised as a Malcorian, during a surveillance mission to see if first contact should be made with the planet.

Berel became aware of Riker's alien nature and the Minister of Internal Security, Krola, was contacted. When the Minister ordered Berel to wake Riker so he could be interrogated, Berel refused, on the grounds that doing so would violate medical ethics. He was relieved of his duties. (TNG: "First Contact")

Berel was played by actor George Hearn. The costume worn by Hearn as Berel was auctioned off (albeit modified for Star Trek: Voyager) in the It's A Wrap! sale and auction.