MAYES COUNTY, Oklahoma - Officers and deputies from nine different agencies joined U.S.marshals in making arrests Wednesday during a sting operation that's been months in the making.

The investigation began last October when a Jennifer McNulty, 38, died from a drug overdose. Police could've just let it go at that, but they learned her 18-year-old son was the one who gave her the painkillers. They started tracing where he painkillers came from and now six people are charged with her murder.

Pryor Police Corporal Chuck Ward led the arrest team we accompanied. After a briefing on tactics and safety, they went to the home of Jennifer McCormack to make the arrest. 

They went early in the day and moved in quickly.

It didn't take long to get her into custody, but to understand where she fits into this case and why it took so long to come together, we have to start from the beginning.

We interviewed Jennifer McNulty, the woman who died of the painkiller overdose last year, back in 2012 when her husband deployed with the military.

Police say her son, A.J., gave her the four oxycodone pills that killed her. They say A.J. bought those pills from Mike Meirs and Jennifer McCormack.

Police say those two bought the pills from Christina Dempsey and that she gets them from her brother for free. The brother was in the hospital when officers went to arrest him.

They say Dempsey also does business with Andrea Gregoire. She's already in jail because police say her baby was born with meth, morphine, oxycodone and other drugs in its system.

"It is not in any way, a victimless crime, there's no way to tally the toll it takes on families," said Brian Surber, Assistant District Attorney for Mayes, Rogers and Craig County.

Police say they spent 10 months getting warrants and going through cell phone records to tie these six people to McNulty's death.

Even though some of them never even met her, the DA says they can be charged because if someone is committing a felony, like drug dealing, and someone dies, the person committing the felony is guilty of murder under Oklahoma law.

"If you're sharing drugs, giving them away or selling them.. if somebody dies, somebody overdoses.... that you are risking being responsible for first degree murder," Surber said.

Police say people think prescription drugs are not as dangerous as other street drugs, but more people in Oklahoma die from painkiller overdoses than from meth, heroin and cocaine combined and they hope this case sends the message, that enough is enough.