The only reason why CNN is picking up the story is because of the lynching aspect. The media loves to race bait these days and anything that does it makes for salacious news reporting.
Usually someone who's going to commit suicide exhibits signs well in advance. Someone who really wants to do it will actually still engage in their normal routines so that no one suspects anything, and they may seem happier than usual because they know everything is about to end. The mother might not have seen it because mothers are often in denial, but I would love to know what his friends, girlfriend, and teammate saw in him in the weeks leading up to this.
If there were no behavioral changes noted among those closest to him, then I would suspect foul play. The banal treatment of the authorities is also suspicious, but there's nothing unusual about police ignoring or minimizing the deaths of minorities. Happens all the time. My intuition is that he was killed, and it was done to make it look like a suicide. It would've been a simple matter to dust the area for fingerprints to find out who else touched the belts used to kill him.
Police are so useless these days.