HAMPDEN, Maine — A package from the country of China that contained 6.5 pounds of bath salts was confiscated last week at the U.S. Postal Service sorting facility in Hampden by the Maine Drug Enforcement Agency.

The seizure is related to the arrest of four people in January in what the MDEA called the biggest bath salts bust in state history that prevented more than $1.2 million worth of the drug from reaching users.

“The package was shipped from China to Leonard Wells in Greenbush,” Darrell Crandall, MDEA’s Division II commander, said Wednesday in a statement about the Feb. 6 seizure.

Drug agents know that Mainers are ordering the outlawed drugs from foreign countries over the Internet, according to Crandall. The agents are partnering with other drug and law enforcement agencies across the country, U.S. Postal Inspectors, and agents with Homeland Security Investigations to stop the illegal packages.

“If you are doing this and you haven’t been caught — stand by,” Crandall said as a warning.

The state enacted laws in 2011 banning bath salts, and later strengthened them to add derivatives and toughen penalties. The federal government enacted the Synthetic Drug Abuse Prevention Act in 2012 that designated bath salts as a Schedule I drug, the same class as heroin and LSD.

The drug, which has caused agitation, hallucinations, paranoia and even psychotic episodes in users and has been linked to a number of deaths since surfacing in Maine in early 2011, is currently more popular than cocaine, local drug agents are saying. Bath salts sell for around $150 a gram, Crandall said.

Wells, 53, and three others were arrested on Jan. 18 by Penobscot County deputies who reportedly caught them divvying up eight pounds of bath salts at a home owned by Wells at 6 New Boston Road in Hermon.

Wells, who has homes in Hermon and Greenbush; Stephen Warren, 29, of Corinth; and Houston residents Arthur Coy, 49, and his girlfriend, Elizabeth Fuentes, 29, were all charged with aggravated trafficking in synthetic hallucinogenic drugs.

The Hermon bust took $563,000 worth of the dangerous drug off the streets, and a week later investigators seized another 10-pound package of bath salts, with a street value of more than $700,000, when they intercepted a package Coy had mailed to himself in Houston.

“The street value of this seizure is $450,000,” Crandall said about the Feb. 6 seizure. “No one has been charged yet in connection with this seizure, but arrests are anticipated.”

Wells was released from the Penobscot County Jail on $50,000 cash bail on Jan. 18, but the other three arrested with him remain behind bars, Crandall said. Coy’s bail was set at $300,000 cash; Fuentes’ at $50,000 and Warren’s at $75,000.

Trafficking in synthetic hallucinogenic drugs is a Class A crime and carries a penalty of up to 30 years in prison and a fine of up to $50,000.

Whether the bath salts from China were ordered before or after Well’s January arrest is a question Crandall declined to answer.

“We know considerably more about this package than we are going to release,” the drug agent said.