OKLAHOMA CITY - Multiple agencies, including the Oklahoma Bureau of Narcotics (OBN) and the Homeland Security Investigations (HSI) shut down a large-scale, Mexican-sourced meth manufacturing operation in Oklahoma City.

As part of a joint investigation into a criminal investigation, OBN and HSI agents were first alerted to the major operation during a traffic stop on Friday near SW 25 Street and Portland, OBN said.

A probable cause search of the vehicle resulted in the discovery of 15.3 pounds of crystal meth, or “ice.”

OBN spokesman Mark Woodward said agents were able to get a search warrant for the driver's home in the 2900 block of SW 39 Terrace.

Inside the home, Woodward said agents found several more pounds of crystal meth, as well as canisters containing multiple pounds of liquid meth that was in the process of being converted into “ice.”

In total, Woodward said this investigation netted 121 pounds of meth in either crystal or liquid form with an approximate street value of $1.5 million.

Woodward said this case is an example of a new meth-trafficking trend by the Mexican drug cartels to avoid detection by border security and U.S. law enforcement highway interdiction officers.

"They are liquefying meth and bringing it in to the U.S. before they crystalize," Woodward said of the suspect's practice.

He said it reflects a trend in the way the cartels are smuggling "ice" into the state but said agents are trained to identify the latest smuggling method.

Pamala Ross lives three doors down from the home.

"I've seen a lot of things coming and going, but nothing like that," Ross said. "You wouldn't think it would be on a nice quiet street in Oklahoma City."

Ross' neighbors, Felipe Martinez, Marisol Nava, and Luis Espinoza were arrested as a result of the investigation. All three are Mexican citizens illegally present in the U.S., authorities said. More arrests are possible as the investigation is ongoing.

This investigation is generated by members of the HSI “Green Twister Task Force” comprised of agents and officers from HSI, OBN, Oklahoma City Police Department, Oklahoma County Sheriff’s Department, and the Canadian County Sheriff’s Department.

“Although our joint HSI investigations with OBN routinely produce significant results to remove illegal narcotics from Oklahoma communities, this seizure of more than 100 pounds of both crystal and liquid meth was especially productive,” said Katrina W. Berger, special agent in charge of HSI Dallas, which also includes Oklahoma. “These seizures and related arrests of three illegal aliens from Mexico is another step to removing this addictive poison from our communities.”

An investigation is now underway to determine if the suspects were working with an larger organization in Oklahoma.