A man lying dead in the crosswalk probably should not be entirely unexpected for a place like New York. With all of the people trying to get around, someone is bound to get off balance at some point. The extent of his injuries, however, changes things a bit. Blood covering the face makes a call to the crime lab a must. Granted, head wounds bleed with the slightest injury. Just to be on the safe side, the professionals need to take a look.
Mac (Gary Sinise) and Stella (Melina Kanakaredes) therefore arrive, along with Flack (Eddie Cahill) for good measure. Hawkes (Hill Harper) is there too, although he isn't strictly needed. A former forensic pathologist makes sense to analyze crime scenes just for a quick idea of what killed somebody. Cops, though, can pretty much tell when a death occurs as a result of homicide rather than by one's own hand. Everything just looks different, no tire marks, so this is not a hit and run. A fall? Doubtful. A quick glance at the angle of the body shows tripping would not put the man in that position.
As it turns out, Hawkes came into contact with the victim, Martin Stafford, earlier in the day. How? Hawkes might not be cutting up dead people anymore, but he still is using his skills by volunteering with a type of first responder group to help the injured when an ambulance might not be able to arrive in time. Hawkes tells Mac it seemed as though the victim was intoxicated, so Hawkes did not stick around too long. A hospital visit might have helped. Then again, as Mac points out, perhaps not.
I doubt anyone would ever tell Hawkes that Stafford died as a result of Hawkes' being neglectful. The weapon of choice is not something one would easily detect unless tests are run. The cause is basically poison, don't bother trying to remember exactly what. It's tricky enough to understand what it is anyway. Suffice it to say the name is not among the usual suspects.