runner on first

Question
From an umpires perspective.
runner on first, batter hits grounder to first about 6 feet from first in the runner path to second. runner on first does not leave the base as batter runner approaches first. first baseman fields the ball and attempts to touch first. the first base runner is still on base and causes the defense to step around to touch first and put out the batter runner.
2 questions: Is the runner on first out due to interference or does she have the right to stay on first even if being forced?
If the batter runner is put out, is the runner on first still safe at first? First baseman never touches the first base runner with the ball.
please explain as this happened to me umpiring in a recreational league game. I called the batter runner out and allowed the runner on first to stay. Just didn't know for sure.

Answer
Bob,

Let's go to the result of the play, you called it correctly.

First nothing in the rules says that your runner on first HAS to leave the base.  On a force play they are in GREAT jeopardy if they don't leave the base.

So you had the runner staying on a base they were being forced to advance from, the fielder never did anything to put that runner out but touched the base to execute the force play on the batter/runner.  When the batter/runner was put out, the runner on first was no longer forced to advance, thus they were protected by being on the base.

What the fielder should have done is tag the runner that was standing on first prior to touching first to execute the force on the batter/runner.  While the runner was being forced to advance they are not protected in any manner by staying in contact with the base.

Tom