Help! - Leaking windows. Seeking ideas and potential contractor

[Blair Nye]

Two southwest facing windows in the top unit of my duplex are leaking water whenever it rains hard. There is no obvious ceiling / wall damage. I have inspected from inside the attic just above the windows and can’t find the source of the leak. My handyman caulked the exterior all around the windows and water is still coming in. 

Any ideas what could be causing the leak? 

Any contractor recommendations? 

Any help is greatly appreciated.