J Mac

This is a high school scenario NFHS Rules: Runner on 1st, batter pops up to first base, runner returning to first base collides with fielder who is still able to complete the catch. is there still interference and both R1 and BR are out? Is contact ignored (similar to catcher being interfered with on a steal but throws runner out) since catch was made and on batter is out? What is the actual rule(s) and case book scenarios for this situation