“The thing that was most noticeable about him was his height and his smile. He always smiled.”

But in the nation’s battle with opioid addiction, William Doerhoff is now a statistic. Another life lost in 2016 to a heroin overdose.

As a freshman at the University of Arkansas, Doerhoff’s problem began with prescription pill abuse – a trend that has become synonymous with the opioid epidemic.

Fueling his addiction, Doerhoff purchased his poison online – and by the end of the year, he was hooked.

“They would crush the pills up and smoke them, or they would crush the pills up and inject them,” Scott Doerhoff said.

His problem came to a head in the summer of 2015, when his mother found him unconscious in his bedroom, barely clinging to life.

Shortly after paramedics arrived, the family realized the severity of his addiction.

“I looked around, and there’s a little piece of foil on the bed and a little bitty plastic tube, and I’m like, ‘What is this?’ And they all looked at me, you know, like, ‘It looks like heroin,’” Shannon Doerhoff said.

He survived the overdose and spent the next year recovering. But in the fall of 2016, he relapsed.

After failing to show up for work one day in October, the Doerhoffs were met with a phone call no parent ever wants to receive.

“As a parent, you know, you just knew. You knew what happened. And it just -- there’s just no way to describe. It’s not really a pain that you feel, it’s like you don’t even know how to exist at that moment because everything that you’d ever done in your entire life, the entire meaning of your life, really, which is to protect your children, had just been taken from you,” Scott said.

Will Doerhoff died on October 14, 2016, at age 20.

Shortly after his passing, Scott and Shannon learned of how their son obtained his fatal dose of heroin: through a purchase on the so-called “dark web.”

In a startling trend that’s sweeping the nation, users are turning to a hidden swatch of cyberspace to feed their addictions.

Not indexed by search engines like Google or Bing, the dark web’s contents cannot be traced back to any one person, allowing individuals to carry out illegal activities and trade illicit goods anonymously.

“Both the seller and the buyer can remain anonymous.”

Chuck Cohen runs the Indiana State Police’s Cyber and Intelligence Division. He likens criminal investigations that reach the dark web to playing a game of digital Whack-a-Mole.

“We’re seeing not just heroin, but other opioids – ranging from Fentanyl to Carfentanil, Opana and others – that are being shipped with great regularity, with the purchase happening in the dark web. The money transactions happen with a crypto currency, and the shipment is being concealed. So, it makes it difficult, increasingly, for us to do those investigations.”

If the so-called dark web and crypto currencies sound like they may be out of reach for the unsophisticated internet user, think again.

Simply visiting a website and downloading free software is more than half the battle.

Popular add-ons like Tor allow users to mask their identities by automatically tapping their devices into a maze of servers planted all over the world, scrambling their true IP addresses in the process.

Arguably the most popular crypto currency in the world is Bitcoin, which trades freely over the internet. Most any user can transfer cash for Bitcoin by simply setting up a digital “wallet” through any number of online exchanges.

Fox News saw firsthand just how simple a dark web drug deal actually is.

“If I wanted to go in here, and I wanted to buy a sampler pack of heroin, it’s going to cost. I click ‘buy now,’ I’m going to log in and create an account – I can do it completely anonymously. Go to my wallet, I give them that, they debit it and, in theory, I’m going to get my heroin in the mail,” Cohen said.

“I can get it shipped to me in a child’s toy or in a computer or in a box full of fruit or whatever that might be. And I can continue to live this lifestyle, but nobody will know. But the person from some global point around the world doesn’t care about John Jones living in rural Indiana, do they? All they care about is the Bitcoin transaction and getting paid for what they do.”

Still, law enforcement leaders say that curbing the epidemic begins with educating Americans about the dangers of prescription pill abuse – since four out of every five heroin addicts begins with pills, according to the DEA.

For their part, Scott and Shannon Doerhoff are raising awareness.

To honor their son, they started the William Christian Doerhoff Foundation and are sharing his story in the hopes that it will save lives.

“Death is final. And our baby is no longer with us. But his message and his story is, and that’s what we want to do,” Shannon said. “We want to be able to speak up and speak out and share. And the more people know, the more lives that are saved.”