Infield Play: Unwritten Rules & Double Play Situations

Question
i had a situation on a popup to the infield.... no out... runner on first...

first baseman lets ball land.... then picks it up and throws to 2b... back to 1b for double play...

is  there any kind of unwritten rule... that would rule  an intentional drop...or letting ball hit ground first... that would keep the fielder from doing this.... ie catching and droping the ball...or... letting it land....  just curious... thank you..

Answer
Hi Greg,

In ASA you must actually catch the ball and then intentionally drop it for a dead ball, batter out, it not unwritten, it's in the rule book.

However for other orgs, intentionally letting drop a fly ball that could be caught w/ ordinary effort is a dead ball, batter out.

Mark