Leak under patio from the ceiling of basement

I am getting the leak from the ceiling of the basement. Interlock patio is just above it. I just moved into the house and most contractors recommended that i re-grade my patio and hopefully that should fix the issue. I got that done but still i am getting the leak. It happens when there is lot of rain only and very little water comes down only in one corner only.

My doubt is it can be caulking around the patio door is culprit but i am not sure. Is there a way to do some tests to figure out if that is the case?

here is the picture of the leak before i re-graded the patio.

 

Welcome to the forums! At what point does your patio intersect that monolithic wall? Is it level with the top of it? Maybe you could post a few pictures of the outside, showing that intersection as well for more information.

 

Pictures inside show us nothing. Need some outside.
Sure sounds like one of the most common building 101 mistakes. Any door openings need to be at least 6" above grade.

 

Thanks guys I will take some pictures and post later today.