Congressional investigators are preparing for former President Donald Trump's impeachment trial by looking at what he and his allies did hours before the deadly riot at the U.S. Capitol building, people familiar with the investigation say.

According to an ABC News report, the House impeachment managers and their team of lawyers are now reviewing materials, which include videos, photos, and social media posts for a possible connection between individuals close to Trump and some of those involved in the violent riot.

A newly surfaced video showing longtime Trump adviser Roger Stone in Washington D.C. on the morning of Jan. 6 was among those that are being investigated.

In the video obtained by the ABC News, Stone was seen taking pictures and mingling outside a D.C. hotel with supporters and members of the Oath Keepers militia group just hours before the deadly riot, including a man wearing a baseball hat and military-style vest branded with the group's logo.

"So, hopefully we have this today, right?" one supporter asked Stone in the video, in which Stone replied, "We shall see." It was not yet known what they were referring to in that particular conversation.

Meanwhile, Stone has reiterated that he played no role in the Jan. 6 event and has repeatedly said that he never left his hotel until leaving for Dulles Airport that afternoon. Stone also maintained that he had no advance knowledge of the riot at the Capitol.

"I could not even tell you the names of those who volunteered to provide security for me, required because of the many threats against me and my family," Stone said in the report.

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Donald Trump Impeachment Trial Focuses on His Role in Inciting Capitol Riot

Looking at Donald Trump's actions, his aides, and allies before and during the riot could help House impeachment managers build a compelling impeachment case against the former president.   

It could also throw light on the acts of those around Trump and whether they could have been familiar with the riot. It could also shed light on the actions of some of those who participated in it - than initially disclosed.

Based on court and military records, interviews, and news reports, ABC News reported that nearly 200 accused rioters face federal charges for their involvement at the Capitol breach. At least 14 individuals who stormed the building have said they were following Trump's encouragement.

Meanwhile, about 150 constitutional scholars claim that Trump has no First Amendment defense in his upcoming Senate impeachment trial.

The law professors and First Amendment litigators said the First Amendment is no bar to the Senate convicting Trump and disqualifying him from holding future office, according to a Law & Crime report.

"The First Amendment does not apply in impeachment proceedings, so it cannot provide a defense for president Trump," they said in an open letter released on Friday.

Trump has filed his official response to the Democrats' impeachment brief on Tuesday, highlighting a planned First Amendment defense.

However, Law & Crime reported that impeachment trials are not actually legal trials. But they are constitutional proceedings that imitate the trappings of law and are ultimately guided by politics above all else. 

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