Denver police are continuing to investigate a Thursday afternoon shooting at a retirement community that left the gunman dead and another person in critical condition.

Around 2:30 p.m., police were called to Metro Manor, located at Quitman Street and West Colfax Avenue, police spokeswoman Raquel Lopez said.

Relatives of the gunman told The Denver Post that he was a resident of the complex and said he had issues with staffers because he did not like them going into his room.

“I just can’t believe it,” said a niece of the gunman. She had rushed down to the scene after she was informed of the shooting.

After an argument with the manager Thursday morning, the man returned in the afternoon with a shotgun and shot the manager, according to relatives and eyewitnesses.

The lobby of the building was taped off as police took pictures and investigated the scene. Behind makeshift walls blocking them from the crime scene, some residents patiently sat, either waiting for updates or to inform those away during the shooting on what had taken place.

Police would only confirm two people were shot in the incident, including the gunman.

Residents who witnessed the shooting in the lobby, near the manager’s office, told The Post that staff members tried to subdue the gunman after he shot the manager.

That is when he turned the gun on himself, relatives said.

The high-rise complex is home to more than 200 people who either are older than 65 or have disabilities, staff said.

Residents of the retirement community were allowed to return to the building around 4 p.m., but the lobby remained sealed off by police for the investigation.

Staff writer Kieran Nicholson contributed to this report.