Lincoln's top drug investigator warned area businesses Wednesday not to sell products containing cannabidiol, a cannabis-derived compound.
State prosecutors said last week the chemical remains illegal despite recent changes to Nebraska law.
Capt. Chris Peterson and Police Chief Jeff Bliemeister said the department agrees with a memo Attorney General Doug Peterson sent to law enforcement and prosecutors statewide Sept. 1.
In his memo, the attorney general said Nebraska law only authorizes the possession of cannabidiol in conjunction with a University of Nebraska Medical Center study and possession of any FDA-approved drugs containing it.
The FDA exception was added to a state law earlier this year.
So far, the FDA has not approved any such drugs, according to the attorney general.
Any possession, distribution or manufacturing of cannabidiol outside of those exceptions is unlawful and will be subject to prosecution, the attorney general's office said.
The memo follows the opening of stores in Omaha purporting to sell supplements containing the chemical, according to media reports.
Cannabidiol is extracted from the Cannabis sativa plant and is distinct from the cannabinoid that is responsible for the drug-related high.
Proponents of medical cannabis have touted cannabidiol as a possible therapeutic treatment for debilitating diseases.
"Regardless of what you find on the shelf in Lincoln or what a store owner tells you, if you know that it contains (cannabidiol), if you possess it or use it, that would be a violation of the law," Capt. Peterson said.
Lincoln police declined to say whether officers have seized any products containing the cannabis compound and would only say the department has several ongoing investigations.
Peterson likened the issue to probes into synthetic marijuana the department led following a spate of K2 overdoses in 2015.
Violators, Bliemeister said, will be held accountable to the full extent of the law and could face prison time and fines similar to those levied against the head shop owners in the K2 case.
Lincoln police will not be inspecting store shelves for lawful products, the drug investigations captain said.
"You have a responsibility to make sure you know what you're selling," Chris Peterson said.
Read Nebraska Attorney General Doug Peterson's full memo on cannabidiol below.