Court documents obtained Tuesday by NBC Montana report that 32-year-old Nathan Calvert was using a substance known as “Spice” for the two weeks prior to a deadly knife attack he’s accused of committing.

Spice is a synthetic cannabanoid manufactured to imitate the effects of marijuana. Consumption of “Bath Salts,” another synthetic compound, is known to imitate the effects of methamphetamine.

The state's been cracking down on these man-made drugs for years now, but Montana State Crime Lab chemist Annalivia Harris says it's a difficult battle.

"The problem came in trying to identify them because so many of them were new compound,” said Harris. “When we have new compounds, we have to prove what they are."

Harris said manufacturers of the synthetic drugs have been able to avoid prosecution by altering the chemical makeup of the substances and selling them legally.

"I think it has helped that the federal government has stepped in and controlled some of these through federal emergency scheduling, but it hasn't helped enough. They just changed the formulations. It's good in (Montana) that we have them controlled now, but it's not controlled nationwide,” said Harris.

Harris said state legislators are currently working with the crime lab on a bill that would broaden the range of chemical compounds that are controlled by state authorities.