A laptop was stolen from a conference room in House Speaker Nancy Pelosi's office during the deadly siege on the U.S. Capitol by supporters of President Trump, a Pelosi aide said Friday.

Why it matters: The theft of the laptop, as well as another computer taken from Sen. Jeff Merkley's office during Wednesday's riot have raised cybersecurity concerns.

• Drew Hammill, deputy chief of staff to Pelosi, tweeted that the laptop taken from the speaker's office was stolen from a conference room and only used for presentations. He did not elaborate.
• Merkely said Wednesday in a video posted to Twitter that rioters stole a laptop that was sitting on a conference room table in his office.

What they're saying: "Materials were stolen, and we have to identify what was done, mitigate that, and it could have potential national security equities," said acting U.S. Attorney Michael Sherwin in a news briefing Thursday, per Politico.

• It will likely take “several days to flesh out exactly what happened, what was stolen, what wasn't,” Sherwin added, saying that “electronic items were stolen from senators’ offices, documents and materials were stolen, and we have to identify what was done to mitigate that [damage]."

Authorities announced Friday they had arrested and charged the man who was photographed sitting at a desk in Pelosi's office.

• Richard Barnett of Arkansas has been charged with three felony counts, including theft of public property, violent entry and disorderly conduct on Capitol grounds.
• Adam Johnson of Florida has also been arrested on a federal warrant and booked into the Pinellas County jail, jail records show. According to Reuters, Johnson was the man photographed carrying Pelosi's lectern from the House of Representative chambers.

Go deeper: Man photographed in Pelosi's office among those charged over deadly riot