Jocelyn Lopez Sanchez started drinking vodka at 15. She moved on to Xanax for depression, then cocaine and painkillers. By 19, she said, "nothing really mattered. I just wanted to be numb."

To support her habit, Sanchez agreed to body-carry 1,000 "Mexican Oxy" pills across the border in Nogales, Arizona.

The following night, Halloween, she took one pill and gave three others of the light blue "M-30" pills to friends. "I didn't really know the difference between the Mexican Percocet and the American Percocet. I just kind of figured it was just all the same. Just a different country."

Big mistake. Within an hour, she began to feel sick.

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"You just feel like death," she recalled. "You want it to be over. You feel out of it. Like, if you're a zombie, and you don't want to be here no more."

As Sanchez prepared to leave the party, she glanced at her friend, Aaron Chavez.

"He was a little more out of it. But at that point, I couldn't tell if he was just tired, or he was enjoying himself."

Hours later, a mutual friend found all three teenagers unconscious and overdosed on fentanyl. When Tucson police arrived, they administered Narcan. Two of the teenagers survived. Chavez, 19 and father of a baby boy, did not. 

"In my eyes, she was guilty all the way, all the way," said Chavez's mother, Leslie. "As for sentencing, I just hope she's able to rehabilitate her life."

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Indicted and charged with "death resulting from distribution," Sanchez faced a mandatory minimum of 20 years to life in federal prison. She pleaded to a lesser smuggling and distribution charge and has been serving a 12-year sentence in a federal prison near Seattle.

"I believe 20 to 25 years is too harsh," she said in telephone interview from prison. "People don't maliciously intend to make someone overdose or hurt anyone. It's just something you don't know what to expect with these pills." 

Sanchez claimed she did not know the pills contained fentanyl. Chavez's mother did not buy Sanchez's story.

"By her knowing they were counterfeit, she had no idea what was in them... really?" she asked. "It's a choice if you're going to be selling illegal drugs."

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Assistant U.S. Attorney Stefani Hepford prosecuted Sanchez. She said under the statute, it does not matter if the dealer knew the drug contained fentanyl or not. 

"The death does not have to be foreseeable," she said from her Tucson office. "We have to prove only that they knowingly and intentionally distributed the drug to the victim, not that they intended for the victim to die."

Convicted in early 2019, Sanchez was among the first street sellers in the U.S. charged with distribution of drugs resulting in death. The intent, prosecutors say, is deterrence - to make dealers think twice about the consequences of their actions.

By the number of fentanyl-related deaths across the U.S., it does not appear to be working. Police also have said the prices of counterfeit pills coming from Mexico have been falling, not rising, suggesting supply is outstripping demand.

When arrested, Sanchez had a two-week-old baby boy.

"It's kind of a difficult situation because I know his family feels a lot of anger towards me," Sanchez said, "but I am sorry. I'm very sad for the people who almost lost their life. Sad over my friend losing his life, thinking about his family, his daughter. But, it should definitely make people think twice if they were in the situation I am in."