A nonprofit government ethics watchdog has requested that a federal agency turn over any documents related to former White House Chief of Staff John Kelly and Caliburn International, the operator of the nation's largest shelter for unaccompanied migrant children.

CBS News reported last week that Kelly has joined Caliburn's board of directors. News of Kelly's new job drew scathing criticism from prominent Democrats, who accused the company of profiting off White House policies that during Kelly's tenure led to a dramatic increase in the amount of time children were kept in government custody.

John Kelly oversaw many of the Trump Admin's most morally repugnant immigration policies. Now he could be making big bucks serving on the Board of a company that's profiting from the same cruel plans he put in place. This is corruption at its absolute worst. https://t.co/1rgpSew8gR — Elizabeth Warren (@SenWarren) May 3, 2019

The nonpartisan organization Citizens for Responsibility and Ethics in Washington (CREW) cited public reaction in its request for the documents.

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"There is a strong public interest in the requested documents. While in government, Kelly was directly involved in implementing the family separation policy, and he now works for a for-profit operator of child detention centers, Caliburn, that has reaped substantial financial benefits from that very policy," wrote CREW attorney Nikhel Sus. "The public has a compelling interest in learning whether Kelly was involved in any communications with or decisions concerning Caliburn or its related entities, both while he was in government and following his departure from the White House in January 2019."

Before joining the White House, Kelly served on the board of advisors of an investment firmed called DC Capital Partners. He stepped down in January 2017 when he was confirmed as secretary of Homeland Security. Six months later Kelly became President Donald Trump's chief of staff, serving through the end of 2018. In 2018, DC Capital folded four of its holdings into a company called Caliburn International

While Kelly was with the White House, the administration took a number of steps to crack down on immigration. One such change is repeatedly cited by personnel with the U.S. Health and Human Services department as having led to a dramatic increase in the average length of stay for an unaccompanied migrant child in U.S. custody.

In June 2018, the government began requiring fingerprint background checks of all household members of a relative seeking to sponsor a child in U.S. custody. Prior to that time, only the sponsor was required to be fingerprinted. The policy was abandoned in December, and HHS officials have since said they did not believe it added value to their system of safety checks for sponsors.

In the months after that policy was enacted, Comprehensive Health Services, a Caliburn company that is the only private company operating a shelter in the country, became one of the most dominant players in the industry. In August, it secured three licenses for facilities in Texas, totaling 500 beds, and in December its Homestead facility in Florida began expanding from a capacity of 1,250 beds, to 3,200.

In a phone call with CBS News on Thursday, CREW's chief ethics counsel Virginia Canter said the organization wants to know what role, if any, Kelly played in decisions that led to Caliburn's expansion.

"We're looking to identify documents that may reveal whether or not he was personally involved in any aspect of these contracts, whether he was briefed on them, or gave guidance with respect to how the government should administer them," Canter said.

CREW is also interested in learning about the approval process by which Kelly gained admission to Homestead for a tour on April 4. All members of the public must be approved by HHS to enter any unaccompanied migrant children's facility. Just four days after Kelly was allowed into Homestead, three Democratic members of Congress — U.S. Representatives Debbie Wasserman Schultz, Donna Shalala and Debbie Mucarsel-Powell — were all denied access.

Canter said there are strict laws governing the actions of former senior White House staff, in particular a statute that bars former officials from exerting influence on decisions made by government employees — even decisions as seemingly insignificant as access to facilities.

"Any request to visit the facility needs to be cleared by the government, and the fact that you have three members of Congress who were denied access shows you that this is not something that is easily obtainable," Canter said.