Sam asked for his help because there is a series of murders that are linked to Hydra and the KGB, and apparently, Bucky is an expert in this. (Unfortunately.) Plus, the killings seem to be connected to an enhanced person for there isn't a lot of struggle and the victims are huge, quite strong men a lot of the time. Bucky doesn't feel comfortable with it, but he agrees to help Sam anyway and take a look at the crime scenes. He used to be an enhanced killer too, after all; he knows where to look and what might be off. Three men are dead already and they got nothing when Sam calls in to ask him over for investigating another murder in fucking Manhattan. It's in one of these fancy office buildings with marble floors and teakwood furniture. The man sits behind his desk, a single cut of his jugular the cause of death. The air stinks of blood and piss. Bucky looks around for a second, then excuses himself to get some fresh air because this hits a little too close to home.
Once he's outside, he fumbles for a cigarette; he's not much of a smoker, but every now and then the sharp taste helps to ground him. Blowing smoke into the air, he looks over to find a girl on the sidewalk. It's hard to gauge the age of kids these days. She could be 12 or 17. "Shouldn't you be in school at this time of day?" he asks. Maybe she saw something if she walks by regularly.