Arizona Republican Sen. Jeff Flake announced Tuesday he is working on legislation restricting certain people from purchasing guns.

Flake took to Twitter to say he and Democratic New Mexico Sen. Martin Heinrich are teaming up to propose a bipartisan bill preventing anyone convicted of domestic violence from buying a gun.

Flake said the conviction would include both criminal and military courts.

Heinrich said the bill would close current "loopholes" and "keep guns out of the hands of those that want to do harm."

This comes just three days after a man walked into a Texas church and opened fire, killing at least 26 people, including children. The suspect served in the Air Force and was court-martialed in 2012 for assaulting his spouse and their child. He received a bad-conduct discharge and was confined for 12 months.

Donald Trump Jr. was quick to criticize the senators' proposal, sarcastically calling it "proactive."

To which Flake responded that closing a domestic violence loophole was in fact proactive.

Earlier Tuesday, it was reported that the gunman escaped from a New Mexico mental health institution.