Ice maker line leaking

Under the island, T'd off the kitchen sink faucet >??

That white line should find its way to a supply line with a small shut-off valve, also you can call Cedar Creek's tech line 260-593-2101 and they will help you. You should hook up your city water so there's pressure in that line and feel the white supply line to see if it's wet from the fridge down then follow it to see if that's the problem.

We see now that the refrigerator is bolted to the floor. We see the white water line running from back of refrigerator then behind cabinet under stove and under the floor. But we don't know where it goes under the floor.

We were going to pull the refrigerator out but could not get it to move. Would it be bolted to floor or do we just need to try harder to move it?

My valve is under the refrigerator.
Did you look there?

If you can't find the valve just cap the water line.