Laurabeth Womack died from a Fentanyl overdose in 2013. The drug was provided in a roundabout way by Robert Everett Bonner Jr. (U.S. District Court)

The way federal prosecutors tell it, Robert Everett Bonner Jr. was a prolific sex trafficker, prostituting more than 55 women and girls as part of one of the largest such ventures law enforcement has ever discovered in Virginia.

Bonner, 34, ruled with deceit, coercion and intimidation, prosecutors said. He recruited women with the promise of a better life, then got them hooked on drugs so he could more easily control them, they said. He used sodomy as a form of punishment, took away the women’s cellphones and IDs so they could not escape, and, in one case, had someone deliver a Fentanyl patch on which a prostitute overdosed, they said.

Authorities in Stafford County encountered Bonner during a prostitution sting at the Days Inn hotel in Fredericksburg in 2013, and, after a lengthy investigation, he was charged federally the next year.

On Friday, a federal judge in Alexandria sentenced him to 30 years in prison for his role in a prostitution ring that operated along the East Coast, authorities said. Prosecutors had asked for the stiff term and noted that had he not agreed to plead guilty in the case, they would have argued for a life sentence.

“The venture was not simply a small-time, neighborhood operation by a part-time pimp,” prosecutors wrote. “It was a well-managed, financially-lucrative, interstate enterprise designed to maximize profits and evade detection by the police.”

[Gangs in Northern Virginia increasingly selling children for sex]

Sex-trafficking cases are startlingly prevalent in Northern Virginia. In another recent example, a 20-year-old Annandale member of the 18th Street gang admitted as part of an agreement with prosecutors that he had prostituted a teenager — with whom he had a sporadic sexual relationship — to pay back a drug debt.

Andrew M. Stewart, Bonner’s defense attorney, argued in a court filing that his client deserved a sentence of 22 years. He wrote that Bonner was not as violent as some of his counterparts in the prostitution ring and that he had accepted responsibility for his actions and “acknowledged that it is a terrible life for everyone involved.”

Bonner, Stewart wrote, has two children, and his friends and family members “describe him as a wonderful and caring father and friend who regularly takes the time to help those in need.” He wrote that Bonner had used drugs from an early age and turned to prostitution to make money after he was laid off in 2011. The Fredericksburg man worked before that in restaurants, operating a laser printer and sealing driveways, his attorney wrote.

Prosecutors took a different view of the case. Bonner, they said, was “one of the leaders” of a sex-trafficking enterprise that operated from New York City to Alexandria to Louisiana and many other spots in between. The umbrella venture, prosecutors said, was called, “Horse Block Pimpin,” although Bonner dubbed his particular part “Ace Block Pimpin.” Bonner and others, they said, recruited women whose phone numbers appeared on backpage.com, then kept them in the enterprise with violence, threats and coercion.

Prosecutors said Bonner “specialized in sex trafficking women who had substance abuse issues,” often getting them addicted to drugs and cutting off their supply if they balked at his demands. In one instance, prosecutors said, Bonner told his girlfriend to deliver a Fentanyl patch to a woman he was prostituting at a hotel in Spotsylvania County in 2013. That woman, 21-year-old Laurabeth Womack, died of an overdose.

Womack’s father, Greg Womack, wrote in materials quoted by prosecutors that every day he relives the phone call by which he found out his daughter was dead.

“I hoped I would see Lolo running up to me, telling me one of her funny stories that made me grin,” Womack wrote. “But my beautiful, happy little girl is dead. She will never do any of those things again.”