EXCLUSIVE

Jarret Stoll had been raging in Vegas with several of his L.A. Kings teammates in the hours before the NHL star was busted for trying to bring a BUNCH of cocaine and molly to a pool party ... TMZ Sports has learned.

Multiple sources confirm ... the Vegas vacation was essentially an unofficial end-of-the-season celebration to unwind and party as a team.

As far as how many Kings were part of the festivities -- sources tell us there were more than a dozen people from the organization on hand ... many of whom continued to party in Vegas throughout the weekend even AFTER Stoll was arrested.

We know Drew Doughty and Martin Jones were part of the Vegas crew -- but they were NOT arrested or accused of any wrongdoing whatsoever. In fact, the only person who got into any trouble was Stoll.