Two men responsible for distributing massive quantities of synthetic marijuana products have pleaded guilty and will be sentenced later this year, U.S. Attorney John Kacavas announced Friday.

Kyle Hurley, 32, pleaded guilty on Tuesday to participation in a conspiracy to distribute and possession with intent to distribute controlled substances. He is scheduled to be sentenced on July 14 and faces a maximum of 20 years in prison. Robert Costello, 71, pleaded guilty back on Feb. 12 to conspiracy to travel in interstate commerce with the intent to commit a drug trafficking crime and to traveling in interstate commerce with the intent to commit a drug trafficking crime. He is scheduled to be sentenced on May 27 and faces up to five years in prison on each charge.

Hurley and Costello were arrested on March 28, 2014, after they arranged to deliver more than 1 ton of synthetic marijuana products to undercover law enforcement officers. The products contained AB-FUBINACA, an illegal controlled substance. The products were sold in packages bearing a variety of brand names, including "Scooby Snax," "Bizarro," "Toxic Blue Magic," and "Caution Platinum." They were then sold in convenience stores and at other locations, and contained chemicals that are unlawful controlled substances.

Undercover law enforcement officers first began purchasing the unlawful products at convenience stores in Hooksett and Londonderry. They then went to Costello, who had been providing the products to the stores, and arranged to purchase larger quantities from him. Costello then introduced them to his source, Hurley, who agreed to supply the undercover officers with large quantities of synthetic marijuana.

Following the arrests of Hurley and Costello, law enforcement officers executed a search warrant at Costello's home in Lawrence, Massachusetts. A shed at the residence was being used to package the illegal products. Seized were 46 kilograms of packaged synthetic marijuana and 24 kilograms of bulk synthetic marijuana, empty packages, shipping documents, scales, heat sealers and flavorings.

A search warrant was also executed at a garage on a property in Seabrook, New Hampshire, belonging to a relative of Hurley. Among the items seized were 16 trash bags each containing 15 kilograms of synthetic marijuana, two trash bags containing approximately 100 packages of synthetic marijuana, 28 boxes containing empty packages, scales, empty acetone containers and shipping materials. In total, approximately 225 kilograms of bulk synthetic marijuana was seized.

A search warrant was also executed at a location in Epping, New Hampshire, where the synthetic marijuana was being manufactured. Among the items located were a cement mixer that was used to manufacture the products, approximately 48 empty 5-gallon drums of acetone, empty chemical containers with AB-FUBINACA residue, three garbage bags containing approximately six kilograms of bulk synthetic marijuana, thousands of empty synthetic marijuana packages and approximately 27 kilograms of packaged synthetic marijuana.

The Drug Enforcement Administration's Tactical Diversion Squad led the investigation, in collaboration with the U.S. Postal Inspection Service and Homeland Security. They were assisted by the DEA-NH and DEA's Air Wing, New Hampshire and Massachusetts State Police, the U.S. Marshal Service, Portsmouth Police, Somersworth Police, Kingston Police, Dover Police and York and Kittery, Maine, Police.

The investigation is ongoing.