So the game might start off more subtle. The big 'attack' described in the intro might not be backstory but something that happens a little further down the line and the team is given a chance to anticipate or respond to it.
For the general tone and structure... imagine a bit of a mystery/manhunt. The task force will be given a number of leads and you guys go out and chase them. Interviewing witnesses, investigating crime scenes, raiding safehouses, general detective stuff. Everyone will probably go out with a partner, and I'll try to mix it up so that people partner swap. IE; The chemist and the field agent go together to investigate a chemical plant in one scene... then the field agent teams up with a behavioral analyst to interview witnesses while the chemist works with a tech geek guy to figure out how the LOVE bomb is weaponized.
So the ideal number of players might be 4-6.
So far we have;
Eoghain mcGleeson, Assistant Special Agent-in-Charge (Tamhansen)
Rose d'Lion, GIGN Special Operative (ShadowFox89)
Jamie Jameson, FBI Special Agent (MistressofPen)
John Jackson, Civillian Contractor (TheFourthShade)
So we have two investigative types, a door-kicker and... whatever it is John would do.
I'll probably not end up using that earlier idea of mine, given how similar it is to Jamie. Though, I can say from experience that I'm kind of apprehensive about any group game that includes a character whose traits include 'doesn't work well with others.'
If you're still interested, Sirian, the scientist niche has yet to be filled.
Other ideas that I can work with...
Nerd labrat. Either a chemist or tech geek, the one prattling away on the keyboard inbetween shots of Jack Bauer shooting dudes. Usually found in the lab doing forensic analysis, but would occasionally go on-site to do field work.
The Informant. Someone who knows something about LOVE from the inside. Probably not a member, but knows some people who are. Hard to say what they'd be at this moment, since LOVE could be a cult, terrorist organization, or a front for something else. If this interests anyone, we can brainstorm ideas about it in PMs. I'm getting project mayhem/fight club vibes though.
The regular. Maybe a cop that was working on this case long before it ever went public. The FBI wants to come in and take over, throwing around jurisdiction... but they're not so willing to give up yet. They've accumulated months or years' worth of evidence and demands to be part of the effort.
I have other ideas, like an administrator type that deals with internal stuff- spokesman/woman stuff or dealing with government and the like... but that sounds boring to play and might be better suited for an NPC.