The Interior Department’s Inspector General is investigating whether six Trump appointees have violated federal ethics rules, it was learned Tuesday.

The six Interior officials are suspected of “engaging with their former employers or clients on department-related business,” reports the Washington Post.

The department has been roiled by a series of ethics and conflict-of-interest investigations since Donald Trump took office.

The latest probes apparently were triggered by a nonprofit group, the Campaign Legal Center (CLC), which alerted the inspector general’s office in February. The office replied last week, saying it had opened the investigation.

The CLC complaint cited reports in the Huffington Post, the Guardian and “extensive public records,” the newspaper says.

The Post notes that shortly after taking office in 2017, Trump signed an executive order requiring his appointees “to recuse themselves from specific matters” involving their former clients and employers.

Those being investigated include Assistant Interior Secretary for Insular and International Affairs Doug Domenech, White House liaison Lori Mashburn and ranking staff members at the Office of Intergovernmental and External Affairs.

The Guardian reported almost one year ago that Domenech had continued to interact with a conservative think tank in Texas where he worked before being appointed to the department.

Benjamin Cassidy, “a former lobbyist for the National Rifle Association, has also attracted significant attention since joining the department for his work on gun-related issues,” the Post says.

The newspaper notes that the investigation revealed Tuesday “comes a week after the office launched a probe into whether Interior Secretary David Bernhardt violated federal conflict of interest rules” involving law clients he previously represented.

Bernhardt’s predecessor, Ryan Zinke, resigned in January after being targeted with several ethics probes.

“Their cavalier approach to ethics appears to have spread throughout the agency, with a pattern emerging where officials have routinely disregarded obligations to remove themselves from official meetings with former employers or lobbying clients,” Delaney Marsco, ethics counsel at the CLC, wrote in an email.

An Interior spokeswoman told the Post in an email that the matters now in question were all reviewed by the department’s ethics officials, and materials relating to the reviews were handed over to the Inspector General.