White House Chief of Staff John Kelly knew that President Donald Trump's staff secretary had issues in his past possibly impeding a permanent security clearance before news reports this week on domestic violence allegations against the aide, people familiar with the matter said.

A deputy chief of staff, Joe Hagin, was concerned that Rob Porter hadn't yet passed a background check more than a year into his tenure and briefed his boss, Kelly, the people said. Porter continued in his high-level job while his bosses waited for the conclusion of the staff secretary's security clearance investigation, the people said.

Kelly and Hagin didn't know the specific allegations against the staff secretary, the people said. Kelly asked Hagin a few weeks ago to dig deeper into why there had been delays in background checks of certain key staff, including Porter. Meanwhile, the Porter that Kelly and other top staff saw every day at the White House was excellent at his job and cordial to his colleagues.