WASHINGTON (AP) – Federal investigators are heading to Flint, Michigan, this weekend to interview residents who complained early on to the federal government about problems with the city’s water supply.

The inspector general’s office at the Environmental Protection Agency says more than 100 people submitted complaints to the agency or the White House between April 2014 – when the city’s water supply was switched to the Flint River – and October 2015, when a public health emergency was declared.

Investigators from the watchdog’s office will hold invitation-only meetings with residents on Saturday to determine how the EPA responded to early requests for help. The interviews will be closed to the media and public.

That office is investigating the EPA’s response to the lead-contamination crisis in Flint.