To that fateful night, which would have been february 26, 2012. >> reporter: for the first time jurors in the george zimmerman murder trial saw the body of the teen-ager he shot, trayvon martin, and heard graphic testimony from one of the first responders to the scene that night. >> did you attempt to see if trayvon martin was still alive? >> yes, sir. i attempted to get his pulse, sir. >> did you detect a pulse on trayvon martin? >> no, sir, i did not. >> they attempted cpr on the 17-year-old. >> i breathed for mr. martin. i tried to. >> what was your role in the cpr attempts on trayvon marti...