Dr. Lynn Webster is a pillar of the pain community. He's an anesthesiologist and pain medicine specialist who's considered a leading expert on how to safely prescribe powerful painkillers. There is no clinical evidence that prescription painkillers are effective over the long term for chronic pain. But Dr. Webster has been preaching these powerful meds can be used for long term pain, provided it is done responsibly. It has come as a surprise to many that the Drug Enforcement Agency is investigating him and he's facing a string of lawsuits after the deaths of multiple patients. Despite all of this, Dr. Webster still has his prescription pad. Dr. Sanjay Gupta has the story.