The change to the department's bio page for Trump - which displayed the text "Donald J. Trump's term ended on 2021-01-11 19:49:00" - created an internet frenzy Monday afternoon.
The flub comes as Trump is under growing pressure to resign and as he faces a second impeachment after his supporters stormed the Capitol last week in a bid to halt the certification of Trump's election defeat to President-elect Joe Biden.
Two people familiar with the incident say the department is investigating exactly how it happened. While the department hasn't ruled out the prospect that the entry was the work of a disgruntled employee, they have yet to reach any conclusions.
The people spoke on condition of anonymity because they were not authorized to discuss it publicly.
The page has since been removed.