The suspect who allegedly pulled a weapon on Capitol Police officers Monday actually was armed with a pellet gun, and not a conventional firearm, sources said – a development that came as a pair of suspicious items prompted a brief investigation Tuesday morning on the Capitol grounds.

Officials have given the all clear after the latest investigation, which was in response to two unattended bags. One was by the East Front of the Capitol near the Capitol Visitor Center steps, the site of Monday’s incident. The other was nearby, at the plaza of the Jefferson Building of the Library of Congress.

The incidents led to the closure of two plazas near the Capitol building, though the Capitol was not put on lockdown, while officers looked into the items.

The investigations reflect the jittery atmosphere on the Capitol grounds in the wake of Monday’s stand-off.

Sources tell Fox News the weapon pulled by the suspect in that incident was an Airsoft pellet gun, though it initially looked like a conventional weapon. 

On Monday, U.S. Capitol Police Chief Matthew Verderosa said the suspect – later identified as Larry Dawson – drew what appeared to be a weapon and pointed it at officers. He was shot and transported to the hospital. He also was charged with assault with a deadly weapon and assault on a police officer while armed.

Dawson, 56, of Antioch, Tenn., has a history with Capitol police. He was arrested in October following an outburst in the House chamber, and a stay-away order was issued, officials told Fox News. 

A bench warrant was issued for his arrest after he was to return to court in November, but did not show up. In January, Dawson wrote the court a letter in which he claimed to be exempt from laws because he is a prophet of God.

A female bystander also sustained non-life-threatening injuries in Monday’s stand-off. 

Fox News’ Chad Pergram and The Associated Press contributed to this report.