Chadwick

From Memory Alpha, the free Star Trek reference.

You may also be looking for actor Robert Chadwick.

Chadwick was a 24th century Starfleet Intelligence operative stationed on Farius Prime. He had been an undercover agent several times.

In 2374, he enlisted Miles O'Brien to infiltrate the Orion Syndicate in order to uncover the Syndicate operative that had inflitrated Starfleet. He later became worried about O'Brien sympathizing with Syndicate member Liam Bilby and even was knocked out by O'Brien, but chose not to mention this in his final report. (DS9: "Honor Among Thieves")

Chadwick was played by Michael Harney.