More charges have been filed against several chiropractors accused of being involved with parallel fraud schemes that allegedly swindled insurance companies out of more than $20 million, the Minnesota Department of Commerce announced Thursday.

A total of 26 people, including seven chiropractors, now face federal charges.

Minnesota Commerce Commissioner Mike Rothman said in the news release that four defendants in the case, all Twin Cities chiropractors, face additional charges of mail fraud and wire fraud. They are Adam J. Burke of Minneapolis, Preston E. Forthun of Bloomington, Huy Ngoc Nguyen of Brooklyn Park and Angela A. Schulz of Chaska.

In March, chiropractor Timothy W. Guthman was charged with one count of conspiracy to commit health care fraud and one count of conspiracy to commit mail fraud. Chiropractors Marlyn C. Comes and Darryl M. Hummeny were charged in December by felony information, which typically signals that a plea agreement is to follow.

The seven chiropractors and others were allegedly taking advantage of Minnesota's no-fault auto insurance law, which guarantees at least $20,000 in medical coverage for policyholders regardless of fault in an accident.

They are accused of systematically paying recruiters, or "runners," to identify victims of car accidents or people willing to claim that they were in a collision.

They then submitted insurance claims and received reimbursements for services that were either not medically needed or were never rendered, according to the charges.

'Runners' also charged

On Thursday, the Commerce Department also announced charges against four more alleged "runners": Mimi Doan of Maple Grove, Okwuchukwu Jideofor of Oakdale, Quincy Chettupally of Brooklyn Park and Mukhtar Hassan of Minneapolis.

Earlier, 15 other runners had been charged.

The alleged schemes were nearly identical, even though executed by different chiropractors, then-U.S. Attorney Andrew Luger said in December when the case was first publicized.

"For the defendants charged in this scheme, what mattered was the ability to get that $20,000, not the patient's need for medical services," Luger said in December.

Twitter: @KarenAnelZamora