Michigan Attorney General Bill Schuette announced criminal charges for three people involved in the Flint water contamination crisis. The water crisis began when Flint’s unelected emergency manager, appointed by Governor Rick Snyder, switched the source of the city’s drinking water from the Detroit system to the corrosive Flint River. The water corroded Flint’s aging pipes, causing poisonous levels of lead to leach into the drinking water.

The three people, two officials with the state Department of Environmental Quality and a water official from Flint -are facing criminal charges as a result of an investigation into the lead-contaminated water case in Flint.  The three men face felony charges including misconduct, neglect of duty and conspiracy to tamper with evidence. They’ve also been charged with violating Michigan’s Safe Drinking Water Act.

The state officials, Stephen Busch and Michael Prysby, work in the department’s water quality section; they’ve been charged with intentional tampering of evidence, among other charges, Michigan Attorney General Bill Schuette said in a press conference Wednesday afternoon.  “We allege and we will prove that Mr. Busch and Mr. Prsyby altered test results which endangered the health of citizens and families of Flint,” Schuette said.  The city employee, Michael Glasgow, is Flint’s water quality supervisor. He’s also charged with tampering with evidence.

A person familiar with the matter said that other parts of state and Flint city government remain under investigation. The prosecution team is trying to uncover more about why the individuals charged, as well as others still under investigation, may have acted the way they did and who may have instructed them to do so, according to one of the sources.

Numerous members of Congress have called for Gov. Rick Snyder and Gina McCarthy, administrator of the U.S. Environmental Protection Agency, to resign over the crisis, which began after Flint switched its water source from Detroit’s water system to the Flint River in 2014 to save money.

That water wasn’t treated properly, and lead from aging pipes leaked into Flint homes and businesses. Elevated levels of lead — which have been linked to learning disabilities — have been found in local children’s blood.

Residents of Flint are using filters and bottled water while the city is under a state of emergency.  On Tuesday, during a visit to Flint, Michigan Gov. Rick Snyder announced he would drink Flint’s water for the next 30 days.  He said wants to prove that when filtered, the water is safe to drink.

Last week, when Snyder encouraged Flint residents to use more filtered tap water instead of bottled water, he “was told by a state official that Flint residents wanted him to start drinking the tap water first.”