A post on social media shows a man who walked through a Walmart in Springfield with tactical weapons and body armor Thursday had criticized Walmart’s gun policy months before the incident.

Springfield police officers say the 20-year-old suspect has been arrested for 1st degree making a terrorist threat. KTTS News will release his name when formal charges are filed by the Greene County Prosecutor’s Office.

The suspect posted on Facebook on February 16th saying, “It’s official. I hate Walmart. Apparently they won’t sell rifle and shotgun ammo if you’re under 21. “New policy”. However, I can walk into the store with a loaded .40 and nobody says anything. What a joke.”

The incident happened Thursday evening at the Walmart Neighborhood Market near Republic and Golden in Springfield.

Witnesses say the suspect walked into the store with a “tactical rifle” and another gun, carrying more than 100 rounds of ammunition. Police say the man was recording himself with a cell phone while walking through the store.

The store manager pulled a fire alarm, signaling people to exit the building.

Police say the man then made his way out an emergency exit where a former firefighter held the man at gunpoint until officers arrived.

Under Missouri law, citizens are allowed to openly carry a weapon without a permit, as long as the firearm is not displayed in an angry or threatening manner. There’s also no age limit to openly carry a handgun, long gun or any deadly weapon.

Police say security video from inside the store would be reviewed to determine the man’s demeanor and a possible motive.

Charges against the man will depend on his actions while he was in the store, said Dee Wampler, a longtime Springfield defense attorney and former Greene County prosecutor.

Carrying an assault rifle in public is not necessarily a crime, Wampler told The News-Leader.

Wampler says, “If he was looking at people in a menacing way or if he was saying something to other customers that was frightening to them — those would be factors.”