In a policy recommendation they described as an important first step toward ending the nation’s gun violence epidemic, experts at the Brookings Institution suggested Wednesday that the minimum age for committing a mass shooting be raised to 21. “Though it would not prevent all deadly gun rampages, tightening the age restrictions on carrying out large-scale, indiscriminate murder is a common-sense reform that could save hundreds of lives,” said firearm policy expert Dan Pendleton, arguing that police should apprehend any mass shooter who fails to present an ID proving they are 21 years of age or older. “If someone is going to shoot up a school, shopping mall, or grocery store, we want to ensure they possess the rational decision-making skills of a mature adult with a fully developed brain. Too young, and they don’t have the judgment necessary to assess whether to pull the trigger on a crowd of innocent people.” The experts also recommended potential killers undergo a mandatory eight-class training course before they can obtain the mass shooter’s license most states require to open fire on the general public.