A Department of Homeland Security employee, Lauren Bullis, was killed on Monday in an alleged shooting and stabbing attack during a violent spree in the Atlanta area.

Authorities say the suspect, 26-year-old Olaolukitan Adon Abel, also allegedly killed one other person and critically injured a third victim during separate incidents.

Officials reported that Bullis was attacked while walking her dog, and DHS described her as a dedicated employee in the Office of Inspector General.

Law enforcement said Abel has a prior criminal record and was later arrested after the attacks, facing multiple charges including murder and aggravated assault, ABC News has reported.

The investigation is ongoing as authorities examine the series of apparently random violent incidents.