Over an 18-month period, agents at the Drug Enforcement Administration and law enforcement officers throughout Nebraska dismantled a methamphetamine trafficking ring tied to Mexico’s notorious Sinaloa drug cartel that shipped large amounts of the drug from California to Midwestern states.

What began in 2013 as an investigation into a mid-level drug dealer led to the arrest this week of at least 20 people along with the seizure of $35,000 and more than 12 lbs of methamphetamine. Authorities also found marijuana and illegal prescription drugs during their round-up.

While the seizure is far from the largest in U.S. history, both local law enforcement and the DEA hailed the effort as a major blow to the drug trafficking organization that operated throughout the Midwest and was responsible for crimes ranging from burglaries to murders.

"We totally dismantled the organization from the higher-ups in California to the criminal users in Omaha," Mike Sanders, the assistant special agent in charge at the DEA’s Omaha office told Fox News Latino. "Not only did it take out the major players but also the low level criminals committing crimes in the community."

Using a number of tactics – such as undercover officers, wire intercepts and controlled buys – law enforcement agents were able to build up a case against the traffickers and track the methamphetamine back to Sinaloa cartel associates operating in California. In September of 2014 investigators seized 5 lbs of methamphetamine transported from California to Omaha.

The Omaha bust highlights the continuing presence of Mexican drug trafficking organizations in the United States – and their expansion away from the border and major urban areas and into more rural regions.

Officials at the Drug Enforcement Administration said that the incursion of Mexican cartels and their proxy groups in the U.S. is nothing new. A Justice Department report from 2011 found that Mexican-based cartels were operating in more than 1,000 U.S. cities between 2009 and 2010 and have expanded from marijuana and cocaine trafficking to heroin and methamphetamine. Also, it noted they are taking part in human smuggling operations as well.

Mexico’s Sinaloa cartel, the country's largest and once headed by the now incarcerated Joaquín "El Chapo" Guzmán, operates in every region of the U.S., according to statistics compiled by the National Drug Intelligence Center.

"Just about every meth seizure we have here – in Nebraska, South Dakota and Iowa – in the past three years has had ties to the Mexican cartels," Sanders said.

Sanders added that the Mexican cartels involved in the methamphetamine trade have been able to corner the drug’s market in the U.S. because they have been able to make a purer but less expensive form of meth in larger quantities.

To do this, the Sinaloa cartel and other groups have hired professional chemists to work in so-called "superlabs" south the of the U.S. border that produce of a form of methamphetamine that sometimes has a purity level higher than 90 percent.

"A few years ago with meth made here in the U.S. it would be brown and just look dirty," Sanders said. "The cartels, however, make it so pure and so good that the meth is clear. It looks like ice."

Along with a growing taste for Mexican meth throughout the Midwest – and in other rural states like Oregon and Washington State – the cartels have moved into these areas in part because of the stepped-up enforcement along the U.S.-Mexico border and better policing of drug trafficking in major urban areas like Atlanta, Los Angeles and New York.

"The main reason for moving to these areas is that the police in cities and along the border have become much more sophisticated in fighting the cartels," George W. Grayson, an expert on Mexico’s drug war and a politics professor at the College of William and Mary told FNL. "When you don’t deal with that type of crime day in and day out you’re not going to have the expertise in combating the cartels."

The DEA and law enforcement in Nebraska said that while this bust will certainly not stop the flow of methamphetamine into the Midwest, it will disrupt the trade into Omaha and the arrests will hopefully help cut back on the crimes like thefts and assaults committed by drug dealers and users.

"It’s a significant amount of meth seized anywhere in the United States," Sanders added.