Massachusetts authorities have indicted 33 individuals tied to a multimillion dollar pay-per-head online sports betting operation.

On Friday, Massachusetts Attorney General Maura Healey announced a 122-count indictment against 33 individuals connected with an illegal sports betting ring that utilized the Costa Rica-based Perhead.com site to track wagers.

Pay-per-head betting sites have become an increasingly popular option with credit bookmakers in the US. The sites, which have been described as ‘Quicken for bookies,’ charge US-based bookmakers a fee per client in exchange for registering and tracking individual bettors’ wagers and win/loss records. The sites don’t handle monetary transactions, as bets are settled up in person twixt bookie and client.

The operation, which was based out of East Boston and South Boston, reportedly handled about $6m in wagers between May 2014 and May 2015, while annual profits were said to be in excess of $3m. Investigators seized $450k in cash, six vehicles and three guns in the course of their arrests.