Lt. Col. Yevgeny Vindman, whose brother, Alexander, served as a key witness during President Trump's impeachment, filed a complaint last week with the Pentagon's inspector general suggesting he was retaliated against for disclosing potential ethics violations by senior White House officials, his lawyers confirmed on Wednesday.

The state of play: Vindman, like his brother, is a decorated Iraq War veteran and served at the National Security Council as a senior lawyer and ethics official. They were dismissed simultaneously in February, though top military leaders, including Defense Secretary Mark Esper, claim they were not politically targeted.

What happened: Details about Vindman's complaint were first made public in a letter from top House Democrats, including House Oversight Chair Carolyn Maloney and House Intelligence Chair Adam Schiff, who asked the Pentagon's internal watchdog to open an investigation into the matter.

• The Democrats say Vindman's complaint alleges he was retaliated against for raising concerns about Trump's 2019 phone call with Ukrainian President Volodymyr Zelensky.
• They also say the complaint alleges that he was removed from the NSC after he reported potential legal and ethical violations and allegations of sexism by National Security Adviser Robert O’Brien and NSC chief of staff Alex Gray.

What he's saying: "There were allegations of sexism, violations of standards of ethical conduct for employees and violations of the Anti-Deficiency Act ... I notified my supervisors on the NSC staff and White House Counsel’s Office about each of these concerns," Vindman wrote in a March memorandum that was attached to his complaint.

• "While any of these infractions are serious, together they form a disturbing pattern of flagrant disregard for rules." 
• "I fear that if this situation persists, personnel will depart and national security will be harmed.  I request you inquire into the facts and allegations herein and take appropriate action."

Read House Democrats' letter about Vindman's complaint.