Today reports based off information from the June search warrant for Michael's home, statements given by the Jackson family to law enforcement-- there was NO heroin found in his home. Marijuana apparently, but not "tar heroin".
The substance that the Jackson family said was "tar heroin " was tested and found to not be heroin of any type.
Here is the LA Times report.
UPDATE: In case you haven't read the 23 page, July 22, 2009 Houston search warrant, here it is in its entirity. Thank you LA Times.
UPDATE: LA Times report saying the supposed "tar heroin" was actually moldy marijuana!