(CNN) -- An off-duty female officer was killed at a Denver jazz concert Sunday night, police said.
The officer was trying to break up a disturbance between two groups at the City Park Jazz concert and was shot in the head, Denver police spokeswoman Raquel Lopez said. She was working security at the venue at the time.
It was not immediately clear what the altercation was about.
Police did not release the officer's name, but CNN affiliate KUSA reported that the officer was a single mother in her 30s and a seven-year veteran of the department.
Lopez said one person was in custody on weapons charges.
KUSA said Denver Mayor Michael Hancock and his family attended the concert, which drew hundreds of attendees.
Read more on this story from CNN affiliate KUSA.