Third out without a force play

[collinb]

I need help on finding a rule. National Fed. Rules
Here is the situation. Two outs with runners on second and third. Ground ball to shortstop who bobbles ball and drops it. Once the runner on second sees the ball bobbled heads to third. Runner on third is heading home on the pitch. The shortstop decides to throw to third. I am base ump sees a tag and calls the third out. Mean while the runner on third crosses home plate before the out. Now a discussion happens on whether the run scores. The plate umpires ask my opinion and I say that if the third out is not a force play and the runner crossed the plate before the third out the run counts.
One of the coaches feverishly goes through rule book for the next two innings and then convinces the plate umpire that the run should only count if the batter-runner made it to first before the third out.
Someone help me here. I can't find the rule the coach showed the plate umpire. As it turned out it was not a close game. Home team 10 visitors 2.

[Edited by collinb on May 3rd, 2001 at 01:27 AM]