Everyone in the small town of Canton is asking the same question, why did he do it? Many have speculated something triggered the incident, but police don't agree. They do say Robertson had a temper and a history of fighting. One charge was back in February.
"He was charged in two counts of disorderly conduct one was a verbal disorderly conduct charge and the other was a physical disorderly conduct charge," says City Prosecutor Bonnie Cade.
The physical charge was dropped, the verbal charge is still pending.
Both incidents involved fights with the athletic department, but not Coach Kinne.
"Coach Kinne, as far as I understand, was the one who defused the situation, the peacemaker at that time," says Cade.
Police Chief Mike Echols says Robertson was known to have a fierce temper and that the department always kept an eye on him.
"We always did. Anytime that we thought he made any kind of threat or was threatening someone, we watched him because we knew he was capable of doing something," says Echols.
Police also say Robertson may have planned the shooting and wanted to die, expecting to be shot by police.
"He done some things around town, paid some bills, indicated to one person that he probably wouldn't be here the next day. Its been rumored he even took out life insurance," says Echols.
According to Echols, Robertson also left a note for his family saying he loved them.
"He was a good neighbor," neighbors like Teddy Cain say they never thought Robertson would shoot someone. Cain says Robertson was always very nice.
"He helped me clean up some of this stuff around here and some of it he didn't charge me," said Cain.
Another neighbor said off-camera Robertson was a wonderful man. That neighbor also says Robertson was very sick, battling a tumor. He speculated that Robertson must have just snapped.