Continued from page 2

A spokesman for the U.S. attorney’s office said at the time that the direct connection between a doctor’s prescription and a patient’s death is difficult to prove.

Prescription drug abuse is so great in the U.S., some agents who once chased Mexican and Colombian drug traffickers are now investigating doctors who push pills illegally, said Payne, the DEA spokesman. But doctors are only one part of the problem.

“We go after the biggest and most egregious cases,” Payne said. “We have to hit the problem at every level.”