Minneapolis School Shooter Tests Multiple Guns at Shop, on Video

Robin Westman -- the school shooter who killed two kids at a Minneapolis Catholic school last week -- went to a gun store days before the shooting ... and handled multiple weapons, security video from the shop shows.

New footage, obtained by KSTP in Minnesota, shows Westman walking into the store around 12:30 PM on Saturday, August 23 ... four days before the shooting at Annunciation Catholic school.

Westman walks around the store ... interacting with staff members and looking down the sight of a pistol and a rifle.

The store's owner -- Kory Krause -- says multiple veteran staff members, who are trained to identify warning signs of potential mass shooter, spoke with Westman ... and none felt the killer was a threat.

Krause says Westman was "friendly" and "jovial" ... and, his team plans to go through every minute of footage to confirm they did everything right in this situation.

While Westman did purchase a .38 revolver, KSTP reports it was not one of the weapons used in the shooting.

As you know ... Westman showed up to Annunciation at 8:30 AM local time on Wednesday, August 27, and fired more than 100 rounds through the church windows during a schoolwide Mass.

Two children were killed and many more people were injured. Westman died of a self-inflicted gunshot wound in the parking lot.

We spoke to a former coworker of Westman's ... who told us Westman asked the security team at the dispensary where they worked about guns. We're told it was the only time Westman mentioned guns at work.