2000 Cadillac Catera Water Leakage

When we have a rain storm or even a light rain for awhile, my wife's Catera gets water on the passangers side floor only, front and back.

I have had the shop check it out but they could not find the problem.

I think the drain holes from the sun roof is plugged or maybe cracked in the line above the floor boards.

Has anyone else had this problem? Would really appreciate the help.