Enjolras had been thinking along the same lines, but Combeferre got there first. (And arguably more efficiently; Enjolras would have sent the message to everyone at once, and will probably still do that later in the conversation.)

He settles back to listen, arms crossed. He can contribute any information he might have if it seems useful, but Joly and Combeferre will have far more incisive thoughts about the nature of this mystery than he does.