The photo you see here was captured off a video we have available of FBI Agents at firearms training circa 1937. You can get more details at the navigation area relative to the '30s videos we've found. It is believed that this photo is that of SA Clyde Tolson.
By all accounts from the few remaining who knew him, Clyde Tolson was a brilliant administrator. But as Hoover's #3 Man, Deke Deloach would comment in his book, "Hoover's FBI," Tolson's main weakness was he wouldn't challenge the Director on various decisions, even when he knew the Director was wrong. I strongly recommend Cartha "Deke" Deloach's book to viewers if you haven't read it.
In his early career, Tolson had roomed with SAC Guy Hottel of the Washington Field Office and both were bachelors. With only grade pay of Agents in the '30s of about $2800 yearly or so, it wasn't uncommon for single Agents to room together to save expenses.
While all men have their weaknesses, one thing you CANNOT say is that neither Tolson nor Hoover stood up for the FBI or tried to set the record straight. In fact, in 1971, Senator George McGovern was making adversarial comments in the press about Hoover and the FBI which were unfounded. Not an uncommon scene even today but the difference is, in this case, Tolson let McGovern know exactly how he felt in a written letter.
In today's world, we'll never see letters to Congressmen or Senators like this again. It would never fit the definition of "political correctness." This is a classic!
page 1 of Tolson's letter to McGovern is here