A federal prosecutor began outlining Wednesday how a loosely organized heroin distribution network supplied the Roanoke region with thousands of bags of the drug.

Speaking in federal court in Roanoke, Assistant U.S. Attorney Don Wolthuis showed a chart of what he said were affiliated heroin rings led by Clifton Dwight "Lite" Lee, Robert Dwayne "Dollar Rob" Early and Alvin Lewis Macauley. Each man had his own chain of suppliers in New Jersey or Philadelphia and distributors in Western Virginia, Wolthuis said. The three sometimes worked together, sometimes separately, he said.

Though details were still sparse, Wolthuis' summary was the most specific account of the workings of the region's heroin scene since law enforcement officials earlier this year began voicing concerns about spreading use among young people.

Lee, Early and four other people were indicted last year on charges linked to heroin distribution. Macauley and three others were indicted separately.

One of Lee and Early's co-defendants, Michael Lee Duggins Jr., is accused of supplying heroin to a juvenile who lived with him in Roanoke County and to at least 26 other people.

On Wednesday, Safiyyah Amirah Omar, who had been indicted with Lee, Early and Duggins, became the first defendant among the related cases to plead guilty.

Speaking through tears, Omar, a 27-year-old Roanoke woman, said she had been an addict in late 2006 when she made at least six trips to New Jersey to pick up heroin for Early.

Omar and her then-boyfriend, Paris Eugene Robinson, carried sealed packages of money for the supplier and purchased between 19 and 25 50-bag bricks of heroin on each trip, Wolthuis said. Robinson was indicted along with Omar.

Each brick cost about $250, or $5 per bag, when bought in bulk, he said. In Roanoke, it could be sold for $25 to $30 per bag.

At the time she was acting as a courier, Omar was using 10 to 20 bags of heroin daily, Wolthuis said. She sometimes sold the drug as well, he said.

More recently, Omar entered a rehabilitation program and with family support has maintained clean drug tests while free on bond, said her attorney, Michelle Derrico of Roanoke.

U.S. District Court Judge Glen Conrad cautioned Omar that because of the amount of drugs involved, pleading guilty to conspiring to possess and distribute heroin -- along with a "detectable amount" of cocaine, in the words of the indictment -- would likely bring at least the mandatory minimum penalty of five years in prison. Omar said she wanted to offer her guilty plea under an agreement that would drop another charge of distribution and possession with intent to distribute.

Conrad said he would take the plea under advisement while a pre-sentencing report is prepared, and he scheduled Omar for sentencing on May 14.

The next hearing in the heroin cases is scheduled to be a guilty plea from Eric Wayne "Cakes" Otey Jr. on Friday.