D. Maltese was a Starfleet officer in the 23rd century.

In 2285, they were a captain at Starfleet Academy's Starfleet Training Command. They were a Beam Technology instructor. Their office, located on the second level of a building, was in room #205. (Star Trek II: The Wrath of Khan, set artwork)

This character was only mentioned in writing.
This officer was named after set designer Daniel Maltese. The placard was sold on It's A Wrap! sale and auction for US$31.99. [1]