At least three people were injured and the suspect was killed after the 22-year-old employee shot individuals at a Smile Direct Club warehouse early Tuesday in Antioch, Tennessee, according to reports.

Security guard Johnny Hardin, 46, was listed in critical condition, according to a tweet from Nashville police. Security guard Carlton Watson, 66, was in stable condition, police said. Smile Direct Club manager Thomas Abbott, 54, was treated and released.

The shooting suspect was identified as Antonio D. King of Nashville, according to reporter Aaron Cantrell.

The shooting suspect began working for the company in June, according to a tweet from the Metro Nashville Police Department. Police said he also worked there from late 2019 until early 2020.

Police also said the shooting suspect acted alone.

King’s family released a statement Tuesday afternoon, according to reporter Tosin Fakile.

Earlier Tuesday, three patients were confirmed by Vanderbilt Medical Center to be in critical condition, according to reporter Rebecca Schleicher.

Three people left the business in ambulances, WKRN reported. Metro police said two employees were shot and brought to an area hospital, according to WKRN.

A witness told WKRN she saw a man shoot out the front doors of the building. She also told the ABC affiliate a security guard was injured in the shooting.

Shattered glass and bullet holes were visible at the site in the 1500 block of Antioch Pike, according to Schleicher.

Smile Direct Club released a statement confirming the shooting and said the incident was contained quickly by on-site security personnel, Fox 17 and WKRN reported.

An employee said they heard a security guard shout, “Don’t pull it out!” before hearing multiple shots, according to reporter Natalie Neysa Alund.

The Tennessee Bureau of Investigation is working independently to investigate the shooting, it said in a tweet.

There continues to be a heavy police presence, forcing a road closure at Antioch Pike and Haywood Lane, according to reporter Josh Breslow.

Officers were called to the warehouse shortly after 6 a.m. (local time), Breslow reported.

This is a developing story. Please return to AJC.com throughout the day for updates.