In three years following the 2016 coup attempt in Turkey, more than 150,000 people have been imprisoned or dismissed from their jobs due to accusations that they were members of terrorist organizations or had carried out terrorist propaganda. Most of the evidence levied against them has consisted of traces of communication signals. These traces have been transformed into signs that, allegedly impartially, index facts related to terrorism. The infrastructure for this is composed of a network of actors located at digital forensics firms, courts, think tanks, and media organizations. I am interested in looking at the interconnected practices that emerge and flow across this network as they produce a form of terrorism expertise that depends crucially on communication signals. How does this expertise on the "signals of terrorism" travel and produce effects? How does the "problem of terrorism" emerge from this network? What are the counter-terror practices that emerge from this configuration, which construe both "the problem of terrorism" and expertise about it? And in reverse: how have digital networks and data technologies been shaped as they serve terrorism expertise? A hypothetical response is that counter-terror is shaped not only by the pre-emption or anticipation of emergent futures, but by a practice of fact-making that follows the signals of an immediate past, composed at the interfaces between digital devices and humans. These new fact-making practices, however, produces an extremely uncertain terrain where both makers and targets of counter-terror feel more vulnerable and precarious. Through fieldwork in digital forensics firms, terror courts, and think-tanks, I will analyze how the practices, methods, and concepts of these very different actors have become connected in a network that – through both overlap and divergence -- generates new frameworks of "terror" and "counter-terror."