Answer:
Everyone thinks T.J is responsible for Mr. Barnett's death because he was always mean and racist to black people in the town.
Eventually, his store was robbed by T.J and the Simms brothers and when Mr. Barnett tries to interfere in the robbery, he is hit over the head by one of the Simms.
T.J Avery is a prime suspect because he is an unsavory character who was known to hang out with the wrong crowd, and he was also one of the robbers.