DETROIT (WWJ) – Federal prosecutors say they will be investigating the fallout from the city of Flint’s contaminated water supply.

The U.S. Attorney’s office confirming Tuesday that they — and the U.S. Environmental Protection Agency — will look into the state’s actions after an unknown number of Flint residents were poisoned by lead in their drinking water.

READ MORE: Lighthouse Partners With Gleaners To Expand Food Relief

Curt Guyette with the American Civil Liberties Union of Michigan welcomes the news.

“You know it’s complicated as to what constitutes negligence verses gross negligence … those are matters of the law and I’m not an attorney, all I can say is there certainly enough smoke here to warrant a criminal investigation, and now to we have to wait to see where that leads,” says Guyette.

In 2014, while under the control of a state-appointed emergency manager, the city of Flint switched its water supply source from Detroit to the Flint River as part of a cost-cutting move.

“The state was denying that there was a problem regarding lead in Flint’s water – when there were clear signals that there was a problem. There’s an open question about whether these actions were criminal or not but whether the state is culpable or not there is no question. They are entirely culpable,” says Guyette.

In October doctors were urging Flint to stop using water from the Flint River after blood tests revealed more children in the city with higher levels of lead.

READ MORE: 3 Dead, 9 Hurt In Separate Weekend Shootings In Detroit

The announcement of the investigation comes one week after the resignation of the former director of the Michigan Department of Environmental Quality, Dan Wyant, as a result of the fallout from Flint.

“I think the state’s response was reprehensible,” says Guyette. “Every step along the way the response by the state was to deny that there was a problem and to attack the people that were trying to sound the alarm. There is certainly enough smoke here to warrant a criminal investigation.”

The ACLU-Michigan is considering legal action against the state.

“You know, everybody in town was put at risk but there is also tens of millions of dollars of infrastructure damage done in Flint as a result of this decision to use this highly corrosive river – so the financial consequences are almost incalculable.”

Flint returned to Detroit’s water system in October. Last week, Gov. Rick Snyder apologized and Michigan’s top environmental regulator resigned.

Tuesday Snyder issued a state of emergency in Genesee County due to the ongoing health and safety issues caused by lead in the city of Flint’s drinking water.

MORE NEWS: Olivia Newton-John, Beloved Singer, Songwriter And Actress, Dies At 73

The MDEQ did not return a call for response from WWJ Newsradio 950 on Tuesday.