A St. Louis shooting this afternoon left four people dead in an a murder-suicide at a health care business on St. Louis’s Cherokee Street.

Two women and two men – one of whom was the gunman – were killed. Based on surveillance footage from the scene, it appears to have resulted from an argument that took place inside the business – A K Home Health Care. All four of the dead are in their 40s and 50s, according to police.

Police say that the shooter appears to have been the owner of the business, and the three victims were members of the staff. The motives behind the shooting remain unclear at this time. Authorities were unsure as to whether the situation developed from an ongoing argument between the owner and his staff.

According to the St. Louis Post-Dispatch, the owner of record for the business is Khadra Muse of O’Fallon, Missouri, a suburb of St. Louis. Police have not yet confirmed that Muse is, in fact, the shooter.

Police response to the incident appears to have been almost immediate. According to witnesses there were officers who happened to be in the area at the time of the shooting. A woman reportedly ran out of the building screaming for help and encountered the officers. It is unclear whether the shooter had already taken his own life by the time officers responded.

The names of the dead have not yet been released, and police have been reluctant to offer more than a few scant details about the situation, due to the fact that the investigation is ongoing.