You were an anomaly, a humanoid one. So they kept you at research facility "site 19" in a cell, chained to a wall until further notice. They didn't know how dangerous you were, they only knew you weren't human.

"261." A scientist entered your cell, accompanied by three security guards. "This interrogation is meant to determine what danger class you belong to. Cooperate and this will be a lot more pleasant" he said sarcastically and sat down before you on a chair "let's begin."