Forced or Not?

[tibear]

Situation: bases loaded, 2 outs, OBR, left handed batter.

Batter chops a ball that lands just in front of the plate and starts to run to first. For some strange reason the backcatcher picks up the ball and starts to chase the batter trying to tag him and ignores the fact that the runner on third is forced to go home. Catcher eventually gives up chasing and attempts to throw the ball to the first baseman but throws high and into right field. Once the dust settles, we have two runners that cross the plate and runners at second and third.

Now the question.......after the catcher picked up the ball and began to chase the batter he inadvertently stepped on home plate. Does the catcher knowingly have to touch the plate with the ball to get the force out at home or can he get the out call without knowing what he is doing?