Ronald J Brockmeyer, who is accused of fixing traffic tickets for himself and associates, was a driving force behind using fines and fees to generate revenue

The judge in Ferguson, Missouri, who is accused of fixing traffic tickets for himself and colleagues while inflicting a punishing regime of fines and fees on the city’s residents, also owes more than $170,000 in unpaid taxes.

Ronald J Brockmeyer, whose court allegedly jailed impoverished defendants unable to pay fines of a few hundred dollars, has a string of outstanding debts to the US government dating back to 2007, according to tax filings obtained by the Guardian from authorities in Missouri.

Brockmeyer, 70, was this week singled out by Department of Justice investigators as being a driving force behind Ferguson’s strategy of using its municipal court to aggressively generate revenues. The policy has been blamed for a breakdown in relations between the city’s overwhelmingly white authorities and residents, two-thirds of whom are African American.

Investigators found Brockmeyer had boasted of creating a range of new court fees, “many of which are widely considered abusive and may be unlawful”. A city councilman opposing the judge’s reappointment was warned “switching judges would/could lead to loss of revenue”.

Brockmeyer, who has been Ferguson’s municipal court judge for 12 years, serves simultaneously as a prosecutor in two nearby cities and as a private attorney. Legal experts said his potentially conflicting interests illustrate a serious problem in the region’s judicial system. Brockmeyer, who reportedly earns $600 per shift as a prosecutor, said last year his dual role benefited defendants. “I see both sides of it,” he said. “I think it’s even better.”

As well as being a judge in Ferguson’s municipal court, Ronald Brockmeyer is also a prosecutor in two nearby cities and a private attorney. Photograph: brockmeyerlaw.com

While Brockmeyer owes the US government $172,646 in taxes, his court in Ferguson is at the centre of a class-action federal lawsuit that alleges Ferguson repeatedly “imprisoned a human being solely because the person could not afford to make a monetary payment”.

“Judge Brockmeyer not being incarcerated is a perfect illustration of how we should go about collecting debt from people who owe it,” said Thomas Harvey, the director of Arch City Defenders, one of the legal non-profits representing plaintiffs who were jailed in Ferguson.

Brockmeyer did not respond to multiple emails and telephone calls requesting comment. Federal tax liens filed against Brockmeyer by the Internal Revenue Service (IRS) state that he has tens of thousands of dollars in overdue personal income taxes from joint filings with his wife, Amy. He also owes tens of thousands in employer taxes for his law firm and an annual tax paid by employers to fund benefits for the unemployed. Since November 2013, Brockmeyer has paid off another three overdue tax bills totalling $64,599.

He owns three properties in the St Louis area and accompanied his family on a vacation to Walt Disney World in Florida in 2013.

The judge was also named among a group of white Ferguson officials found by Department of Justice investigators to be writing off citations for themselves and friends while punishing residents for similar offences. Another of these officials, court clerk Mary Ann Twitty, was fired by the city in connection with racist emails also uncovered by the inquiry.

The report said Brockmeyer agreed to “take care” of a speeding ticket for a senior Ferguson police officer in August 2014, and had a red light camera ticket he received himself from the nearby city of Hazelwood dismissed in October 2013.

“Even as Ferguson city officials maintain the harmful stereotype that black individuals lack personal responsibility – and continue to cite this lack of personal responsibility as the cause of the disparate impact of Ferguson’s practices – white city officials condone a striking lack of personal responsibility among themselves and their friends,” the Justice Department investigators said, in a scathing report on the city’s administration.

The class action lawsuit filed against Ferguson earlier this year alleges that the city violates the constitutional rights of defendants imprisoned over outstanding tickets and minor offences. It seeks compensation and asks a federal judge to force Ferguson to halt the practices.

“Once locked in the Ferguson jail, impoverished people owing debts to the city endure grotesque treatment. They are kept in overcrowded cells; they are denied toothbrushes, toothpaste, and soap; they are subjected to the constant stench of excrement and refuse in their congested cells [and] they are surrounded by walls smeared with mucus and blood,” said one passage of the lawsuit, which went on to name several more hardships.

One of the plaintiffs – Roelif Carter, a 62-year-old disabled military veteran – alleges he was arrested and jailed for three days in Ferguson in 2010 after trying to pay the $100 monthly instalment for his outstanding traffic fines on the second day of the month rather than the first, when it was due. While living in “constant fear” he was arrested and jailed three more times in the following years when he was unable to pay the monthly charge, the lawsuit alleges.

“Most debtors in this country are not rounded up and jailed in brutal conditions,” said Alec Karakatsanis, a co-founder of Equal Justice Under Law and a lead attorney on the lawsuit. “But if you happen to owe your debts to a municipality in St Louis County, they are willing to let you languish there on a ransom.”