Politicians and news organizations have said since last year that Mexican drug cartels are operating throughout the United States and in more than a thousand American cities, according to a federal government report. But that report—produced by a now-defunct agency—may have been way off.

The report in question came out of the National Drug Intelligence Center (NDIC), which used to be part of the Department of Justice until officials closed it down last year and folded the NDIC’s duties into the Drug Enforcement Administration (DEA).

Based on what the NDIC reported, media outlets and members of Congress informed the public that as of 2011, Mexican criminal organizations, including seven major drug cartels, were operating in more than 1,000 U.S. cities.

After conducting its own investigation, The Washington Post reported this week that the number is “misleading at best,” Scott Higham, Sari Horwitz and Steven Rich wrote.

Law enforcement officials and drug policy analysts told the newspaper that the figure was inflated because NDIC relied on self-reporting by police, instead of using documented criminal cases involving Mexican drug-trafficking organizations.

Some local police chiefs were surprised to learn that the NDIC claimed cartels were operating in their cities.

“That’s news to me,” Randy Sobel, chief of police in Middleton, New Hampshire, told the Post.

David Lancaster, chief of police in Corinth, Mississippi, said he had no knowledge of Mexican drug rings at work in his area.

Officials at the DEA and Justice Department said they have no confidence in the accuracy of the list compiled by NDIC.

One man who scoffs at all this is NDIC’s most recent director, Michael F. Walther, who oversaw the agency for seven of its 19 years. “It doesn’t surprise me that the DEA doesn’t support those numbers,” he told the Post. “They like to paint a more positive portrait of the world. I stand by the work that our analysts did at NDIC.”

But many concur with the results of the Post’s investigation.

“They say there are Mexicans operating here and they must be part of a Mexican drug organization,” Peter Reuter, who co-directed drug research for the nonprofit Rand think tank and now works as a professor at the University of Maryland, told the Post. “These numbers are mythical, and they keep getting reinforced by the echo chamber.”

That reinforcement continues through testimony by lawmakers and top military officials, as well as congressional reports and even the 2012 study (pdf) by the House Homeland Security oversight subcommittee on violence and terrorism on the Southwest border.

“Once the number is out there and it comes from a source perceived to be credible, it becomes hard to disprove, almost impossible, even when it’s wrong,” John Carnevale, a former drug policy official who served four White House “drug czars” and three U.S. presidents, told the Post.

-Noel Brinkerhoff, Danny Biederman

To Learn More:

Mexican Drug Cartel Activity in U.S. Said to be exaggerated in Widely Cited Federal Report (by Scott Higham, Sari Horwitz and Steven Rich, Washington Post)

Drug Cartel Used BofA Account to Invest in U.S. Racehorses (by Noel Brinkerhoff and David Wallechinsky, AllGov)

Drug Cartel Money Laundering in U.S. Is Devastating Unless You’re a Bank (by Noel Brinkerhoff, AllGov)