Michigan's attorney general will announce criminal charges on Wednesday connected to his investigation into dangerous levels of lead in Flint's drinking water, the Detroit Free Press reported on Tuesday.

The newspaper said that among those who will be charged by Attorney General Bill Schuette is a Flint city official who signed a document saying the homes Flint used to test tap water under federal guidelines all had lead service lines. Investigators allege the statement was false.

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The newspaper cited three sources familiar with the investigation for its story.

Flint, a city of about 100,000 people, was under control of a state-appointed emergency manager in 2014 when it switched its source of water from Detroit's municipal system to the Flint River to save money.

The river water was more corrosive than the Detroit supply and caused more lead to leach from its aging pipes. Lead can be toxic and children are especially vulnerable.

The move has provoked a national controversy and prompted lawsuits by parents who say their children are showing dangerously high blood levels of lead.

The Free Press quoted two other sources familiar with the probe as saying Schuette would announce felony and misdemeanor charges against two to four people.

The investigation is continuing and more charges are expected, sources told the newspaper. The charges will be brought against people connected with the Michigan Department of Environmental Quality and the city of Flint.

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Schuette, a Republican who is widely expected to run for governor in 2018, opened an investigation in January. A spokesman for Schuette could not be immediately reached for comment.

The Free Press reported that a person familiar with the matter said that other parts of Michigan state and Flint city government remained under investigation.

Flint went back to Detroit water in October.