Federal authorities on Wednesday announced the indictment of 54 individuals in a Manhattan-area drug-dealing operation that distributed deadly fentanyl-laced heroin and other drugs.

The charges punctuate a three-year investigation into the operation by local and federal law enforcement agencies. A series of arrests were made between Kansas and Chicago, where the drugs were supplied, authorities aid.

Five defendants are charged in connection with the death of Kansas State University student Maxwell Dandaneu, an 18-year-old who died in 2017 from an overdose caused by fentanyl. If convicted, the defendants would face a minimum of 20 years in federal prison for the overdose death.

U.S. attorney Stephen McAllister, the chief prosecutor for Kansas, said this case is one of the largest takedowns of a drug operation in Kansas history.

The case demonstrates the growing threat of opioids in Kansas, McAllister said. Fentanyl is a powerful, synthetic painkiller. Drug dealers mix fentanyl with heroin and pass it off as OxyContin, he said. The combination can be deadly for someone like Dandaneu, who was trying drugs for the first time.

Even a few grams of fentanyl — an amount almost too small to see — can be deadly to anyone who isn't already an addict with a tolerance, McAllister said.

"We're seeing crazy behavior, and we'd like to get the word out," McAllister said. "A teenager who thinks they are trying heroin, like the K-State student, may unfortunately be quite wrong about that. It may well contain deadly fentanyl."

McAllister said the painkiller is manufactured at labs in China and Mexico and smuggled into the United States. The drug has become so prevalent, drug dealers also supply Narcan, which can be used to reverse the effects of an opioid overdose.

"We've seen couples, addicts, who say: 'OK, you shoot up first, I've got the Narcan. If you overdose, I'll revive you. Then it's my turn,' " McAllister said.

Individuals charged in the drug operation also are accused of dealing methamphetamine, ecstasy, hydrocodone and marijuana. Other felony charges involve conspiracy, firearms and communications.

Federal prosecutors and officials from Riley County and Junction City police departments, U.S. Marshals Service, FBI and Drug Enforcement Administration revealed details of the investigation during a news conference at the federal courthouse in Topeka, where defendants were expected to appear throughout the week. Authorities still were trying to locate several defendants.

Officials dubbed their efforts "Operation Chicago Connection" because of the pipeline between Chicago and Manhattan.

Dennis Butler, director of the Riley County Police Department, said officers directed their attention toward chronic criminal offenders who were consuming police resources. The ensuing investigation uncovered a distribution ring, and officers linked the organization's activities to Dandaneu's death.

"Those indicted were directly involved in criminal activity that changed lives, damaged personal relationships and caused premature deaths," Butler said.

Riley County police Capt. Tim Hegarty said the drug operation could be linked to additional deaths, including several individuals who would have been defendants in the case.

Prosecutors describe the operation a single criminal network with levels of hierarchy. Manhattan became a base of distribution for drugs that were sent elsewhere in the state, they said.

McAllister said authorities focused their attention on Manhattan, which has a population of about 56,000, because the size of the city made it easier for law enforcement to wrap up the organization. Authorities regularly seize large amounts of drugs in other areas in Kansas, he said, but it is difficult to tie those arrests to larger operations.

"Manhattan was an opportunity to really clean out a city, and we don't get that opportunity all that often," McAllister said.

William Callahan, a regional special agent for the DEA, said the three-year investigation culminated in a series of high-risk arrests as officials seized drugs, guns and cash.

The DEA's goal, Callahan said, is to identify, investigate and dismantle these types of drug operations.

"Those charged today are not facing drug trafficking charges for the mere possession of recreational use of drugs," Callahan said. "The DEA targets those who prey upon people who suffer from the disease of addiction for their own greed."