FALL RIVER, Mass. — With his ex-teammates about to play in the Super Bowl, former New England Patriots star Aaron Hernandez went on trial on murder charges Thursday, watching from the defense table as prosecutors said DNA on a shell casing and security-camera video from his own home connect him to the crime.

Hernandez’s lawyer countered that the NFL player had “the world at his feet” and had no reason to kill. He repeatedly told jurors that the athlete is innocent and said authorities “locked” in on him as a suspect early on, ignored evidence and conducted a “sloppy and unprofessional” investigation.

Hernandez, 25, is charged in the 2013 shooting death of Odin Lloyd, a 27-year-old semipro football player who was dating the sister of Hernandez’s fiancee. Lloyd’s bullet-riddled body was found in an industrial park near Hernandez’s North Attleborough home, not far from Gillette Stadium.