Texas school shooting: Suspect's grandmother upgraded to good condition

The accused gunman in Tuesday's deadly school shooting purchased two AR-15-style rifles at Oasis Outback, a federally licensed store located in Uvalde, law enforcement sources told ABC News.

A general manager at Oasis Outback told ABC News that he is working with law enforcement but would not comment on whether the alleged shooter did or did not purchase his guns there.

Oasis Outback is located approximately 3 miles from Robb Elementary School.

According to the Bureau of Alcohol, Tobacco, Firearms and Explosives, the alleged shooter made his gun purchases on two separate days: May 17 and May 20. That means he bought the first AR-15-style rifle one day after he turned 18 and the second four days before the shooting.

Both weapons were purchased at that same store, Steve McCraw, the director of the Texas Department of Public Safety, confirmed during a press conference Wednesday afternoon.

The guns were purchased legally.

-ABC News' Josh Margolin, Aaron Katersky, Laura Romero and Olivia Rubin

The House will move on a bill to create a national red flag law, according to House Majority Leader Steny Hoyer, D-Maryland.

The bill would allow family members or law enforcement officers to "petition for an extreme risk protection order with respect to an individual who poses a risk to themselves or others."

The bill is sponsored by Rep. Lucy McBath, D-Ga., whose 17-year-old son Jordan Davis was fatally shot in 2012.

Hoyer said on Twitter Wednesday that he plans to bring the bill to the floor when the House returns from recess next month.

-ABC News' Lalee Ibssa

The gunman warned about the shooting in private messages on Facebook minutes beforehand, a spokesperson for Meta said Wednesday. The warning on Facebook was made in "private one-to-one text messages that were discovered after the terrible tragedy occurred."

The gunman sent three messages on Facebook about 30 minutes before the shooting saying: "I'm going to shoot my grandmother," "I shot my grandmother" and "I'm going to shoot an elementary school," Texas Gov. Greg Abbott said at a press conference.

Abbott said the suspect was reportedly a high school dropout. Officials have reportedly not identified a criminal history for the suspect, but Abbott said he may have had a juvenile record, but that is yet to be determined.

Abbott said the suspect did not have a known mental health history.

According to the ATF, the shooter made his gun purchases on two separate days: May 17 and May 20.

Beto O'Rourke, a candidate running for governor of Texas, interrupted a press conference held by current Gov. Greg Abbott Wednesday, shouting at Abbott before being escorted from the building.

O'Rourke protested the current governor's stance on gun control.

"You are doing nothing!” he shouted.

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Beto O'Rourke interrupts Texas governor's press conference on shooting

O’Rourke was escorted out of the press conference after a heated argument between himself and Lt. Gov. Dan Patrick

ABCNews.com