Richmond police say they received a tip that helped them thwart a mass shooting on the Fourth of July.
Mayor Levar Stoney said officers "quietly investigated" to stop "what could have been a terrible day for the city of Richmond."
Two men, who were roommates in Richmond, have been arrested and charged in connection with the investigation, Richmond Police Chief Gerald Smith said Wednesday. Weapons and more than 200 rounds of ammunition were seized from the suspects' home.
The apparent plot would have targeted Richmond's Fourth of July celebration at Dogwood Dell, a city-owned amphitheater, officials said.
"The broad outline is that they were planning to actually shoot up our Fourth of July celebration," Smith said.
Smith said "a hero citizen" overheard a conversation that there was a mass shooting being planned in Richmond.
The citizen called Richmond police July 1, and the department began an investigation that day with the Department of Homeland Security and the FBI, Smith said.
The investigation took authorities to the 1000 block of Columbia Avenue in Richmond. Inside a home there, they saw evidence "in plain view" that corroborated what the witness had said, Smith said.
Authorities seized assault rifles, a handgun and 223 rounds of ammunition from the home, Smith said.
At that time, the first suspect was taken into custody. Julio Alvardo-Dubon, 52, is charged with being a non-U.S. citizen in possession of a firearm. He is being held at the Richmond city jail.
Smith said officers surveilled a second suspect and watched him throughout the holiday until they had probable cause to make an arrest. The second suspect, Rolman A. Balacarcel, 38, was taken into custody Tuesday and charged with the same counts as the first suspect.
It was not immediately made clear what the probable cause was in the arrest of the second suspect. Smith said officers would have acted quickly if they saw that suspect attempt anything.
"If he were to try any act of violence, our officers would have acted swiftly and beforehand," Smith said. "We were watching and very, very closely. … Not trying to sound evasive, but [if] the officer saw him making any violent moves, they would have acted very swiftly."
Both Stoney and Smith stressed the importance of the tip that came in from a member of the public.
"We've seen the proliferation of weapons of war being used on our civilian population throughout this country," Stoney said. "We've seen it in Uvalde. We saw it in Buffalo, and unfortunately, we saw [it] this past Fourth of July, in Highland Park, Illinois. And that's why it's very, very important that we remember the phrase 'See something, say something.'"
Smith said that while authorities know what the suspects' intent was, their motive was not yet known.
He said the suspects had not been previously known to the Richmond Police Department, and officers had not had any earlier encounters with them before the tip came in.
"The success of this particular investigation can only be juxtaposed against the horrors in which the rest of the country has seen," Smith said. "There is no telling how many lives this hero citizen may have ... saved from one phone call."