old movie has an older man I think is a lawyer and a teenage boy in it. The boy witnesses a murder or beating I think in a corn field. and convinces the old man to help him prove it. the old man may be of some other profession but has an office in town set in a small town as I remember
My guess is it is Intruder in the Dust, but some of the details are off.
Anyway, the entire movie is currently on YouTube.