Beverly Lewis 
Mystery of Case D. Luc (Cul-de-Sac Kids Book #6) 

Dunkum’s new basketball has been signed by his hero, David Robinson. Now Dunkum spends all his time playing with the ball. He’s much too busy for his Cul-de-sac friends.When the ball disappears, Dunkum finds a secret code. Someone with a weird name has stolen the basketball! And he’s leaving messages everywhere! Who is the mysterious Case D. Luc? And will the codes lead Dunkum to his treasured ball?The Mystery of Case D. Luc was chosen as a C.S. Lewis Noteworthy Book