Police now say the person who was found dead inside a vacant building nearly 24 hours after exchanging gunfire with security guards was a transgender woman.

The incident began when private security guards were called to a building in the 4200 block of Barnaby Road SE for a possible intruder about 9:45 p.m. Sunday.

As they checked each of the vacant apartments, they found an armed suspect, police said. The suspect and one guard fired their weapons at each other before the suspect took off, police said.

Police responded and searched the building with a K9 but couldn't find the person.

Guards believed the person had left, but on Monday, officers were called back to the building, where a transgender woman was found dead with trauma to the body, Police Chief Peter Newsham said Tuesday. Police initially said the suspect was a man.

Newsham said police believe the woman is the same person who traded gunfire with the guards.

Police found a handgun at the scene.

The security guards work for Metropolitan Tactical Elite Protective Services, police said.

Earline Budd, a D.C. activist and advocate for sex workers, told News4 she has heard that the boarded-up building has been used for sex work.

She said she doesn’t understand how police did not find the woman during the initial search Sunday night.

Police say the investigation is still active. They will release the woman's name once they have notified her family.

The medical examiner will examine the body.