I actually stumbled on your post. Next time, please start a new post so everyone can see it. As a matter of choice, you can still do it. I'll just follow the new one but for now, I'll see if I can get you started ...
If you know there's a french drain and sump pumps where the leak is, maybe the drain is clogged. Find where the pump drains its water. Maybe that water is making its way back to the basement. Also, review the landscape and see where the downhill-effect is by working your way BACKWARDS from the low point nearest the leak. For example, I use to have a water problem but NOT from water on my lot. THere's an apartment complex behind me, and when there's a steady or prolonged or short, heavy rain, the runoff from the asphalt driveway ends up running into my yard. I noticed this during a heavy rain when I went outside to see how water was flowing during a heavy rain. Since the water was from natural runoff, the complex's owners weren't liable to fix the problem.
Just be sure that your gutters aren't overflowing and that your downspouts are not clogged and that they're at least 3' from the foundation and that you have positive, landscape sloping AWAY from the foundation. If you're thinking there's an underground spring or something that's causing the problem, it's possible but a reach IMO.
My best to ya and hope this helps.
PS: This months issue of The Family Handyman has a good article in it about installing a french drain with downspout connections and a drywell. If you go that route, get the issue if you decide to do this work yourself. I guarantee you it's back-breaking work!