Tragedy struck St. Louis, Mo. Thursday after a disgruntled worker came into his office and proceeded to shoot up the establishment before killing himself, resulting in a grisly murder-suicide. Officials are still trying to piece together exactly what happened.

The shooting occurred at AK Home Health Care LLC, which is in the Cherokee Place Business Incubator south of downtown St. Louis. The shooter is alleged to have been either a owner or co-owner of the establishment, and there have been rumors that the aggression was triggered by a "brief" argument, though those claims have yet to be substantiated.

"We don't know if this was a thing that carried over into today or was initiated today," St. Louis Police Capt. Michael Sack said.

Sack also noted that the victims appeared to be in their 40s and 50s and were all employees of the business. So far no pictures or names of any of the parties involved have been released to the public, though one person at the scene claimed to know them.

"They always smile for me. This is my worst day in my life. It's a very, very sad day for us and a very sad day for the city of St. Louis," said Abdi Salam Elmi, an immigrant from Somalia who drives a cab in the area.

The Cherokee Place Business Incubator is located just a few minutes away from downtown, and was built a decade ago in what was once a thriving business section of the city. As one local expert observes, this type of violence is not common for the area.

"It's not like this type of thing goes on down here. This is very much a shock to us," said Jason Deem, a board member and former president of the Cherokee Street Business Association. "Everything police are telling us leads us to believe it was a targeted incident and not some random act of violence."

St. Louis has long been known for its problems with urban violence. This week alone city policemen have had to respond to five different shootings that left 15 people injured, not including Thursday's violence.