Las Vegas shooter Stephen Paddock was prescribed anti-anxiety medication that can cause aggression this summer, according to a report.
The 64-year-old, who killed 58 people and wounded hundreds during his Sunday night massacre, was written a prescription for 50 pills worth of diazepam, brand name Valium, in late June, records seen by the Las Vegas Review-Journal show.
It was not immediately clear why the shooter, who lived northeast of the killing scene in a town called Mesquite, would need the medication.
He was also given the same dose, 50 10-milligram tablets, in 2016.
The prescribing physician, Dr. Steven Winkler, did not answer questions from the Review-Journal or confirm that Paddock was a patient.
Mass shooting at Mandalay Bay Hotel and Casino in Las Vegas
Diazepam, a benzodiazepine, is normally used to sedate people, though studies have shown that it can also be associated with aggressive behavior.
Columbia University researcher Dr. Michael First told the Review-Journal that it would more likely be associated with impulsive acts of violence than the intricate planning that went into Paddock’s killing.
The gunman brought a small arsenal of guns into the Mandalay Bay Resort and Hotel to fire on concertgoers below.
Investigators have not released a suspected motive for the shooting.