A woman was arrested after she allegedly knocked her sister unconscious early Tuesday morning in Leavenworth, a police spokesman said.

The incident was reported at 1:09 a.m. in the 800 block of Ottawa Street after someone flagged down a police officer.

The 37-year-old suspect allegedly struck her 22-year-old sister in the head with an unknown object, according to Maj. Dan Nicodemus, deputy chief of the Leavenworth Police Department.

The victim reportedly lost consciousness but was awake when the officer arrived on scene. She was taken to the hospital.

The suspect was arrested for an allegation of aggravated domestic battery. She reportedly was in possession of a substance that is believed to be cocaine, according to Nicodemus.