Four men with ties to Mexico face federal charges involving the seizure of approximately 20 pounds of fentanyl in Clark County, Ohio, by members of the Miami Valley Bulk Smuggling Task Force.

During a press conference Thursday, Ohio Attorney General Mike DeWine said approximately 20 pounds of fentanyl were seized during a joint task force investigation and was enough to kill 3 or 4 million people, according to My Dayton Daily News.

Omar Alejandro Cantu Garcia, 28; David Guillermo Cantu Garcia, 30; Pedro Torres Medina, 40; and Reyes Espinosa Aguilar, 43, (also known as Rodrigo Martinez Jr.) were each charged with one count of conspiracy to possess with intent to distribute fentanyl.

According to an affidavit filed in support of the criminal complaint, Omar Cantu and David Cantu entered the United States from Mexico via the Laredo Port of Entry on Sunday, June 10. All four suspects have ties to Mexico and one was later determined to be in the U.S. illegally, according to Montgomery Sheriff Phil Plummer.

According to the press release from the United States Attorney’s Office from the Southern District of Ohio, task force investigators observed two suspects exit a hotel in Dayton and later observed activity consistent with drug trafficking which included vehicles being taken on a “heat run,” which is a common countersurveillance technique used by drug traffickers to check if they are being followed by undercover officers. “Heat runs” consist of various actions such as a driver speeding up and slowing down, driving into a dead-end street and parking to see if anyone is following, or returning to its original location while looking out for ground or air surveillance.

Police surveillance later observed suspects meeting at gas station parking lots and transferring packages between vehicles–which eventually led to traffic stops. One vehicle, which was stopped by Clark County Sheriff’s Deputies, contained eight vacuum-sealed packages of cash which totaled over $150,000 USD. The investigation then led to a search inside a residence where agents discovered at least 100 pounds of marijuana sealed in plastic bags in the garage and nine-kilogram blocks of fentanyl in a closet.

The street value of the fentanyl seized was said to be $3.6 million (USD).

Conspiracy to possess with intent to distribute fentanyl is punishable by 10 years up to life in prison.

Robert Arce is a retired Phoenix Police detective with extensive experience working Mexican organized crime and street gangs. Arce has worked in the Balkans, Iraq, Haiti, and recently completed a three-year assignment in Monterrey, Mexico, working out of the Consulate for the United States Department of State, International Narcotics and Law Enforcement Program, where he was the Regional Program Manager for Northeast Mexico (Coahuila, Tamaulipas, Nuevo Leon, Durango, San Luis Potosi, Zacatecas.) You can follow him on Twitter. He can be reached at robertrarce@gmail.com