I don't buy the fact that Jay was so afraid of being busted for dealing drugs that he became a snitch in exchange for immunity. But, assuming he was a dealer on some level, and he possibly sold drugs from grandma's house, the cops could have threatened him by claiming they would seize grandma's house pursuant to the state's civil forfeiture laws as a drug dealing location.

The civil forfeiture laws are pretty rough, and in some instances the state (and some municipalities) are permitted to take real estate free and clear of any other liens on it, including prior mortgages (though that's rare). That could be a basis for getting him to cooperate. However, it seems that if that threat was made, it would have to be revealed per Brady v. Maryland and Giglio v. US because that's a clear reason for Jay to lie and an excellent source of impeachment of his testimony by the defense.

Thoughts?