Four people were shot to death in a reported murder-suicide inside a building in St. Louis, Mo. Thursday afternoon, according to CBS St. Louis.

Police confirmed two adult males and two adult females killed in the Cherokee Place Business Incubator, at 2715 Cherokee St. at around 1:40 p.m. Thursday. St. Louis Police Capt. Michael Sack said in a press conference Thursday that the three victims were employees of a health care business. The shooter reportedly appeared to have been arguing with them prior to opening fire with a semi-automatic weapon he had.

The St. Louis police captain said that it was unclear if the shooting was premeditated.

"We don't know if this was a thing that carried over into today or was initiated today," he said.

CLICK HERE for photos from the scene.

Dozens of police officers rushed to the complex between Ohio and Iowa Aves., and sealed off the area Thursday afternoon.

On Thursday evening, the Metropolitan Police Department of St. Louis released in a statement the identities of the four who were killed. The victims were listed as Khadra Muse, 44; Seaeed Abdulla, 29; and Bernice Solomon-Redd, 54. The suspect was identified as Ahmed Dirir, 59.

The building, a converted movie theater, houses many individual businesses, according to the news station. The shooting occurred between the Marine Villa and Soulard neighborhoods of the city, south of downtown St. Louis. Onlookers told FOX2now that three people were taken from the office in handcuffs but were later released, after police discovered them to be witnesses.

Somalian immigrant Abdi Salam Elmi told The Associated Press he knew all four of the people killed, saying that they were all hard-working. He said, "They always smile for me. This is my worst day in my life," adding that it was also a tragic day in St. Louis' history.