Easy, remember that time they took down some Vampires (or any other horror)? Well they remember that red-haired agent and the creatures friends are looking for him (or her).
Now the baddies will recognize the heroes, probably before the heroes recognize who the baddies are...
A muck-raking reporter has a beef against the agency and he distinctly remembers a certain tall agent...
A particularly nasty creature exclusively eats red-heads...
An underworld boss puts a bounty on red-heads and really tall agents...
A succubus really likes tall people, now the agent has a love-struck demoness following him around...
Just a few ideas.