St. Louis TV news reported tonight that he first tried to get the AR-style rifle from an FFL but was turned down (reason unknown). He then proceeded to acquire one through a "private sale". Antis are jumping all over this aspect, complaining how "lax" the laws are in Missouri.
Other reports (multiple) have informed us that at one point members of his family told the police that he was a danger to himself, and the police confiscated the rifle. The police subsequently released to rifle to a family member (not identified in the reports I've seen.)
Wasn't there another mass shooter fairly recently who was in the same situation? Cops took his gun (or guns), released it/them to a family member, and the shooter miraculously had his gun(s) back.
Maybe the antis should be jumping on the family member who gave him back the gun.