The tennis shoes used in this episode, as evidence, are a pair of Jack Purcell sneakers. This is visible when the police show Perry Mason the sneakers. You can see the Purcell "smile" on the toe, in-laid logo in the sole, and smooth sole.
Della: Well this is certainly a poor substitute for the chicken cacitore you promised me. Client?
Perry: Walter Frazer. Wonder what will happen when his investment company is under the management of an overaged juvenile delinquent.