Democrats on the House Oversight and Government Reform Committee want to reopen its investigation into the Flint, Mich., water crisis, according to a letter written by ranking member Elijah E. Cummings of Maryland and released Wednesday.

The investigation, which led to a high profile oversight hearing that turned into partisan finger-pointing last March, was quietly closed before the Christmas holiday by Chairman Jason Chaffetz, R-Utah.

Democrats say they were not consulted on the decision, and that questions about how the crisis occurred, who bears responsibility and the progress of recovery remain unanswered.

“When you traveled to Flint on March 12, 2016, you said you wanted to know ‘who knew what and when and what did they do,’ ” the Democrats wrote in their Jan. 17 letter to Chaffetz. “Unfortunately, prematurely closing the investigation last month without obtaining key documents and hearing from dozens of officials contradicts this promise.”

“We ask you to reconsider your decision and to join us in taking the steps we have outlined,” the letter added.

Democrats want a committee vote on issuing a subpoena to Michigan’s Republican Gov. Rick Snyder that would compel him to provide the committee key documents that Democrats argue could provide answers as to what and when Snyder knew about the crisis.

Snyder appeared before the committee last March, accepting some responsibility for the crisis, but putting a large chunk of the blame on the Environmental Protection Agency for failing to timely and publicly disclose the problem. Republicans echoed the EPA blame, while Democrats targeted the state as the main responsible party.

The letter also requests criminal referrals to the Department of Justice for three state employees, including the Flint emergency managers Darnell Earley, Gerald Ambrose and Edward Kurtz for allegedly impeding and misleading the congressional investigation.

Chaffetz closed the investigation on Dec. 16 in a letter to the chairmen of the Energy and Commerce and Appropriations committees, respectively. The letter, which did not offer any new information, placed blame on both the state and EPA and recommended that most congressional action should be related to regulation oversight.

Chaffetz’ office declined to comment.

The Flint water crisis continues. Residents of the city are still unable to drink from the tap without using a filter, and many are still opting for bottled water.

“The Flint water crisis is not over,” Rep. Dan Kildee, D-Mich., said in a statement. “Flint families deserve not just resources to help them recover, but also justice in the form of holding those who did this to Flint accountable.”

Congress in last month’s continuing resolution did direct a $170 million aid package to help the city repair its lead-contaminated water system.