Special counsel Jack Smith plans to present former President Donald Trump’s cell phone data as evidence during his federal election interference trial, according to new court filings.

Smith’s office filed a notice Monday saying prosecutors plan to call several expert witnesses during the trial to explain Trump’s cell phone use during and after the Jan. 6, 2021, insurrection at the Capitol. One witness, Smith wrote, has “extracted and processed data” from White House cell phones used by Trump and “specifically identified the periods of time” when the devices were unlocked and the Twitter application was open.

The three expert witnesses were not identified in the filing.

Their testimony could bolster Smith’s argument as he seeks to describe to a jury Trump’s behavior and social media use around the time of the Capitol attack. Politico notes, however, that it could be difficult to prove what activity Trump was directly involved in himself since others helped maintain his social media presence while in office, including social media manager Dan Scavino.

Trump was indicted in August over his efforts to remain in power after he lost the 2020 election to Joe Biden. Prosecutors have charged him with four federal counts, alleging the former president engaged in a multi-pronged conspiracy to stay in office and subvert the will of the people.

He has denied all wrongdoing.

Smith also obtained access to Trump’s personal Twitter account earlier this year as part of his investigation. The revelation prompted fury from the former president, who accused his office of “breaking into” the account and “trying to completely hide this atrocity from me.”

“What could he possibly find out that is not already known,” Trump questioned at the time.

The trial is scheduled to start on March 4, the day before Super Tuesday, a major day of elections in the 2024 presidential primary. Despite his four indictments and his refusal to appear at the GOP debates, Trump remains the far-and-away frontrunner for the Republican nomination.