General Da Smoove -- another member of CSD -- tweeted last night, "Sickle cell took my brother away from me today."
Smoove adds, "With that being said I'm proud to know that with that disease he made the best of his life ... I jus(sp) saw my bro literally fight for his life I told him 'I love you bro' hope'n he heard me."
Sadly, Jay is not the first member of Cali Swag to die ... in 2011, CSD member M-Bone was murdered in a drive-by shooting.
JayAre was 25.