. >> narrator: jim carruthers was one of those short sellers.tarted his own investment firm. >> someone had told us that there were only a small number of doctors that were, um, approximately, you know, 50% of their entire revenue. remember, this is a drug that, it specifically had warning to be given to breakthrough cancer patients only we discovered that the primary prescribers are pain med doctor and then, when you did any kind of background check on these pain med doctors, wh you really found was, in our opinion, pill mills. >> narrator: by then, subsys was turning up in federal busts of pill mills across the u.s. >> there are a couple of things going on that are incredibly helpful. ne u.s. attorney's office michan is prosecuting a doctor out there named gavin awerbuch. they've talked to patients, they've done surveillance, they've actually had some undercover buys. at one pointhe was the largest prescriber of subsys in the ited states. >> narrator: gavin awerbuch was in fact insys's biggest whale. for $138,000 in speaking fees and her gifts