Sen. Richard Blumenthal, D-Conn., wants Congress to investigate the use of solitary confinement on immigrant detainees in Department of Homeland Security custody.

Blumenthal's call for congressional hearings came after the publication of an NBC News investigation in partnership with the International Consortium of Investigative Journalists and the Intercept that documented the extensive use of solitary for immigrant detainees held in jails around the country.

"This report should shock the conscience of every member of Congress," Blumenthal said in a statement to NBC News on Friday. "Putting immigrants fleeing for their lives in solitary confinement, alone and away from any human contact for days, weeks, months is inhumane. It is un-American."

The investigation found that Immigration and Customs Enforcement was regularly forcing people into solitary confinement often for reasons that had nothing to do with them breaking any rules.

Only half of the almost 8,500 solitary cases between 2012 and 2017 involved punishment for rule violations. The other half was made up of reports involving people — who are gay, mentally ill or disabled — put in isolation largely for what ICE described as safety reasons, according to the documents obtained by NBC News and its partners.

The story chronicled the attempts of a Department of Homeland Security employee to sound the alarm on the rampant use of solitary on the mentally ill and other vulnerable people in ICE custody.

"We have created and continue to support a system that involves widespread abuse of human beings," that employee, Ellen Gallagher, said.

"I commend the courageous whistleblower for coming forward," Blumenthal said Friday. "We must open an investigation, seek testimony from DHS whistleblowers and hold individuals responsible for these abhorrent conditions and policies."

Blumenthal began calling for a congressional investigation hours after the story published Tuesday, tweeting that "Congress must seek testimony from DHS whistleblower & investigate."