U.S. Sen. Amy Klobuchar, a former Hennepin County attorney who is now sponsoring some of the federal legislation, called the growth of synthetics a "major shift" in the drug trade.
"I think it's only going to get worse if we don't start getting serious about enforcing these laws and giving the prosecutors and cops the tools that they need," Klobuchar said.
Federal agents who have devoted their careers to America's war on drugs are scrambling to find a way to fight a problem emerging with a different set of rules.
"We're going to be constantly having to deal with this issue of 'legal' stuff coming on the market," said Rusty Payne, a Drug Enforcement Administration (DEA) spokesman in Washington. "This is stuff that's dangerous."
A tiny package, bought online
More than a week before the deadly Oklahoma party this spring, college student Cody Weddle visited a little-known chemical website and placed an order, court documents allege. He and others had researched 2C-E, an investigator said. Internet posts describe it as a sensory-enhancing psychedelic similar to LSD. A user nicknamed "Easy Rider" told Web readers about her "joyful night" on 2C-E, which made her feel "very warm and happy" and "more in control of myself than the drunk people around me."
Weddle compared it to Ecstasy and bought one gram of the powder for $120, investigators say. He had it shipped to his parents' house. When the tiny package arrived 10 days later, court documents say, he met with friends and fellow university students Andrew Akerman and Anastasia "Stacy" Jewell, who were dating. The students mixed the powder into a one-liter bottle of water.
For Akerman and Jewell, at least, it wouldn't be their first bout with drugs. Both had been in trouble for marijuana before. A friend said Jewell had done Ecstasy several years earlier but hadn't used drugs for a while.
Oklahoma public records show no prior convictions for Weddle. His attorney, Rob Neal, recently described Weddle as a "very well-mannered young man" who worked nights in a doughnut shop.
Weddle took some of the tainted water with him when he left Jewell's house that day, court documents say, and she and Akerman kept the bulk of it in an Aquafina bottle. Weddle told investigators that Akerman and Jewell were going to take the bottle to a party outside Konawa that night.
Konawa, a poor rural community about 70 miles southeast of Oklahoma City, was Akerman's hometown. The tallest structure on the small town's main drag is the white steeple of the First Baptist Church, and, until recently, the sole restaurant was a Sonic drive-in.
Akerman was supposed to sell the tainted water for $1 a milliliter -- less than a thimble full -- and he and Weddle would split the profits, according to court records. They stood to make more than eight times what Weddle paid for it.
At some point in the day, someone took a red marker and scribbled the water bottle with a skull.
No dealer, just the Web
Finding instructions for mixing, making, dosing and ingesting synthetic drugs is simple on the Internet. Erowid.org, one popular website, suggests mixing psychoactive powders into liquid to make it easier to measure accurate doses without expensive scales.
The Internet is also a flourishing marketplace for potential users to buy designer synthetics. One of the most popular online merchants appears to be am-hi-co.com, a site that acknowledges some of its "potpourri blends, incense and collectors items" may not be legal in all countries. In June, an estimated 8,156 people visited the site, up from just 515 unique visitors two years ago, according to data analysis by Internet Exposure, a Web design and research firm hired by the Star Tribune. Several other sites selling synthetic drugs had similar growth.
Merchants are introducing new products online, too. When the DEA temporarily banned five chemicals used to make synthetic marijuana early this year, retailers started promoting new mixtures they claimed were not covered by any bans.
The market is too lucrative to disappear. Herbal incense, sometimes called synthetic marijuana, accounted for nearly $5 billion in sales last year, according to an estimate from the Retail Compliance Association, a national retailers group that formed to challenge herbal incense bans.