St. Louis, MO – An off-duty St. Louis Metropolitan police officer was accidentally shot and killed at the home of another officer early Thursday morning, police said.

The off-duty officer, described as a 24-year-old female with over two years on the force, stopped by the Dover Place residence of an on-duty officer just before 1 a.m., after the on-duty officer and his partner had also gone to the home, KMOV reported.

Details surrounding the circumstances of what transpired prior to the shooting were not released, but the female officer was shot in the chest during the encounter, St. Louis Police Chief John Jayden said during a 2:30 a.m. press conference, according to the St. Louis Post-Dispatch.

The on-duty officers, described as 29-year-old males with nearly two years on the force, sent out an “officer in need of aid” alert at 1 a.m., and rushed the wounded female officer to St. Louis University Hospital.

She was pronounced dead a short while later.

“We are deeply saddened to announce that the officer transported to the hospital has succumbed to her injuries,” the department said in a predawn tweet on Thursday. “We ask that you keep the officer’s family and the entire SLMPD in your thoughts and prayers as we mourn the loss of our officer and friend.”

St. Louis Police Officers Association (SLPOA) Business Manager Jeff Roorda said that the union wants to understand the circumstances surrounding what occurred just as much as everyone else does.

“But for now, we wait; we wonder; and we weep,” the SLPOA said, according to KMOV.

“She served her community and her nation with dignity and courage both as a police officer and as a member of the military,” the statement read. “That is how she lived, as a hero. And, for now, that is all anybody needs to know.”