FARGO, N.D. (AP) - A Texas man accused of selling synthetic drugs to customers in every state and distributing the chemicals that resulted in the overdose deaths of two teens in the Grand Forks, North Dakota, area was sentenced Thursday to more than 20 years in prison.

Charles Carlton, 29, of Katy, Texas, is the 15th and final defendant sentenced in the case that began after 18-year-old Christian Bjerk, of Grand Forks, and 17-year-old Elijah Stai, of Park Rapids, Minnesota, died within a week of each other in June 2012 after ingesting the hallucinogens.

Investigators said that Carlton, a self-described connoisseur of hallucinogens, sold the chemicals to Andrew Spofford of Grand Forks, who cooked up the drugs that killed the two teens and sent three other young people to the hospital. Spofford was sentenced earlier to more than 17 years in prison.

"It all rests on that initial decision to sell drugs for money," U.S. District Judge Ralph Erickson said before sentencing Carlton to 20 years and 6 months in prison. "It's as bad as it gets."

Carlton pleaded guilty in March to three counts: conspiracy to distribute controlled substances resulting in serious bodily injury and death, introduction and delivery of a misbranded drug and money laundering. He faced a maximum penalty of life in prison without parole.

Carlton's lawyer, Alexander Reichert, said during Thursday's hearing that the government wrongly fixated on his client as the "worst actor they had ever seen" when there were others in the conspiracy who were just as culpable and received lesser sentences. Reichert said Carlton agreed to be interviewed for a documentary on synthetic drugs as a public service.

"He is desperate to make amends for what he has done," Reichert said.

It wasn't immediately clear what prison term Reichert had been seeking, and he left without taking questions after the hearing.

Carlton owned 51 percent of Motion Resources LLC, a former Houston company that allegedly imported controlled substances from Asia and Europe and made hundreds of thousands of dollars by reselling them over the Internet to domestic buyers. It is illegal to sell the chemicals for human consumption.

Federal prosecutor Chris Myers said Carlton continued to sell the chemicals when he found out about the two North Dakota deaths and filled out paperwork to change the name of the company.

Erickson ordered Carlton to pay back $385,000 in drug proceeds.

Myers, who asked for a sentence of 25 years, said afterward he was pleased with the outcome in a case that was complex on "so many different levels," including dealing with an unknown substance and the wide reach of online sales. He said there's no way of telling how many customers were hurt by the business.

"The response by state, local and federal law enforcement in the case was unbelievable," Myers said. "From the time these kids were found deceased until search warrants were executed in Texas was approximately two months. They dismantled an international drug trafficking organization and undoubtedly saved lives."

Debbie Bjerk, as she has in previous sentencing hearings in the case, showed a video of her son in his football uniform during a parents' day event eight months before he died. She also put a photo on a big screen showing Christian celebrating what would be his last birthday. He would have turned 21 on Tuesday.

"He not only stole the lives of Christian and Elijah, he stole the lives of the other 14 defendants before him," she said of Carlton. "There are no healing words I can say today that can convey the magnitude of our loss."

Unlike earlier hearings, Debbie Bjerk showed a photo of her son in his casket and Stai on life support at the hospital.

The judge said he received 25 letters of support from Carlton's relatives, friends and co-workers and believed that by most accounts that Carlton was "a devoted husband, good father, excellent employee and worked hard."

When given his chance to speak, Carlton turned to the Bjerk family and apologized.

"If I could turn back the hands of time, I would," he said, fighting back tears. "I have two children of my own, and what happened to your children is my greatest fear as a parent."