Ex-NBA Player Javaris Crittenton -- Conspired to Buy 400 KILOS Of Cocaine ... Cops Say

Disgraced NBA player Javaris Crittenton was part of a MASSIVE drug ring -- that was hoping to move 400 KILOS of cocaine and 10 POUNDS of weed ... this according to legal docs obtained by TMZ Sports.

We broke the story ... the former Washington Wizards player was arrested in Atlanta last week during a sting operation that netted 20 suspects ... some with stereotypical drug cartel nicknames like "Crutch," "Chop" and "Carlito."

FYI -- 400 kilos is roughly 881 pounds. That's A LOT of blow.

Officials say the drug ring has been operating since at least 2012.