Mubarak, ousted during the country's February revolution, is on trial for murder in connection with the deaths of unarmed demonstrators.
Egyptian Police Capt. Mohamed Abdel Hakim Amar was charged with perjury after he denied security forces were armed with live rounds during the initial stages of the revolution. Lawyers representing family members of those killed during the revolution said this was a reversal from earlier testimony in which he said he was given orders to shoot, Egyptian news agency al-Ahram reports.
Four senior police officials in the trial against the president testified they didn't receive direct orders to kill protesters.
At least 25 people were injured, including 14 policemen, when clashes broke out after the trial resumed Monday.
Prosecutors want more testimony in the case against Mubarak, including from U.S. Secretary of State Hillary Clinton and former Egyptian Vice President Omar Suleiman.
Suleiman had told Egyptian prosecutors early this year that Mubarak knew of the events unfolding during the revolution, receiving hourly updates about the unrest from his interior secretary.