It really sounds like an expansion of SP, you know, just like Halo 4 Spartal Ops, and the price make's a possibillity that it is but perhaps Crytek didn't mentioned yet. I think ( for me ) the price it's to much elevated for only a MP DLC..
Maybe the signal they track is Nomad's Nanosuit or something like that, remember "I've found him, i found Nomad.."