DETROIT (AP) – Flint’s water crisis has taken a dramatic turn with criminal charges being filed against two state employees and a city worker. Michigan Attorney General Bill Schuette alleges the three men knew that a lack of corrosion control in drinking water was a threat to public health and intentionally tampered with lead-level reports to cover up the fiasco.

It’s an extraordinary step to haul mid-level public employees into court on such allegations, especially when the public’s perception of corruption typically involves bribes or other favors. Gov. Rick Snyder has said his environmental regulators didn’t use “common sense.”

READ MORE: The Detroit Zoo To Host Its Final Weekend Of Family-Friendly Halloween Event 'Zoo Boo' Oct. 22-24

Flint pulled water from the Flint River for 18 months until last fall but didn’t add corrosion-control treatments that could have prevented lead from leaching out of old plumbing. The city is struggling to recover, six months after switching to another water source; it’s still considered unsafe to drink unfiltered tap water.

The following may help answer questions of whether authorities found illegal conduct or are trying to criminalize bumbling performance during a major government failure:

What are the charges?

It’s a mix of felony and misdemeanor crimes.

Stephen Busch and Michael Prysby of the state Department of Environmental Quality and Flint utilities administrator Michael Glasgow are charged with tampering with evidence. Busch and Prysby are also charged with conspiracy, misconduct in office and violations of drinking water law. Glasgow is additionally charged with willful neglect of duty while operating the water plant.

Busch and Prysby have pleaded not guilty, while Glasgow hasn’t appeared in court.

What’s the most serious allegation?

The evidence-tampering charge refers specifically to 2015 reports on lead levels in water samples, and carries a maximum penalty of four years in prison.

Glasgow’s attorney, Robert Harrison, said the charges against his client “are difficult to understand.” He said Glasgow was a source for investigators, freely speaking over many days without a lawyer.

READ MORE: Tillson Street's Halloween Displays Draws Thousands

The charges suggest actions by the three went “above what would be the normal, perhaps imperfect, performance” of public employees, said Linda Fentiman, a professor at Pace Law School in New York.

Will this have a chilling effect on public employees?

Snyder has taken responsibility for what happened in Flint, but he’s also repeatedly blamed bureaucrats in his administration for not properly treating the river water for corrosion and endangering public health. Criminal charges, the governor said, have taken the saga to a “whole new level.”

In 2014, eight days before Flint switched to the Flint River, Glasgow told a state official that he wasn’t comfortable but felt pressured by bosses to move ahead.

Snyder sent an email Wednesday to more than 40,000 state employees, saying he’s proud of their work and doesn’t want the charges to “hang like a cloud” over their service. But Ray Holman, a lobbyist for the United Auto Workers, which represents state workers, said there was already a culture of “fear and intimidation” before the charges.

Will there be more charges?

Schuette didn’t waffle Wednesday: He guaranteed more charges in a $1.5 million investigation being led by former FBI agent Andy Arena and special prosecutor Todd Flood. “We’ll go wherever the truth takes us — in this case wherever the emails take us,” Schuette said, referencing the bushels of emails by state, county and city employees who made decisions about Flint water.

“High-profile conspiracy cases will get worked from the bottom up,” said Kevin Collins, a former federal prosecutor in Texas, who’s not involved in the Flint probe.

The attorney general said no one is off limits. Arena, who built a career busting corrupt politicians, appealed to people who committed wrongdoing but want to cooperate: “Usually the first person on the train gets the best seat.”

MORE NEWS: Kalamazoo Tests For Lead Exposure Following High-Lead Level Reports In Other Michigan Cities

Copyright 2016 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.