Attorney General Bill Schuette charged two high-ranking state health officials today in the fourth round of criminal charges in the Flint drinking water crisis.

Michigan Health and Human Services Director Nick Lyon is charged with involuntary manslaughter and misconduct in office, both felonies.

Chief Medical Executive Eden Wells is charged with obstruction of justice and lying to a police officer.

Wells is accused of knowing about the deadly Legionnaires' outbreak and covering up the source, according to charging information read Wednesday morning in district court in Flint.

Both are charged in connection with the Legionnaires' disease outbreak in the Flint area that led to 12 deaths after the city's water supply was switched to the Flint River.

So far, 15 current or former state or City of Flint officials have been charged, including two emergency managers who were appointed by the governor and reported to the state treasurer.

Flint's drinking water became contaminated with lead in April 2014 after the city switched from treated Lake Huron water supplied from Detroit to raw water from the Flint River, which was treated at the Flint Water Treatment Plant.

Michigan Department of Environmental Quality officials have acknowledged a mistake in failing to require corrosion- control chemicals to be added to the water. As a result, lead leached from pipes, joints and fixtures into Flint households.

Though lead levels in the water have come down significantly since the state acknowledged the contamination around Oct. 1, 2015, residents are still advised not to drink tap water without a filter. Many still rely on bottled water, which can be picked up free at distribution centers in Flint.

Five of the current or former state employees charged previously are from the DEQ. Three are from the Department of Health and Human Services (DHHS).

Outbreaks of Legionnaires' disease in the Flint area following the water switch were tied to the deaths. Officials haven't definitely linked the water switch to the disease, but Schuette and his investigators have come close to doing so in public statements and documents related to the criminal charges.

Lyon was told in September by state investigators that he was a focus of the investigation, Lyon's lawyer Larry Willey of the Grand Rapids criminal defense firm Willey & Chamberlain told the Free Press in October.

"We haven't heard from them for months," Willey said late Tuesday. "I've received no notification ... that anything is in the offing."

Gov. Rick Snyder named Lyon director of DHHS in April 2015 when he created a new agency that merged the former departments of community health and human services.

Previously, Lyon had served as health direcot beginning in September 2014, Before that, he was the agency's chief deputy director beginning in 2011.

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