Diamond Reynolds, 27, was arrested along with two other women accused of attacking a 24-year-old victim and striking her with a hammer.
The woman who gained global attention last July after she live streamed the aftermath of her boyfriend's fatal shooting by police was arrested Thursday in connection to a hammer assault.
Officer Jeronimo Yanez shot at Castile seven times after he told him he was armed.
Ramsey County, where the three women were taken into custody, has asked a neighboring county, Washington, to take hammer attack case and handle any charges, over concerns that Reynolds's arrest could cause a conflict of interest.
At about 10:30 a.m. Tuesday, St. Paul police officers responded to a 911 call about an assault in progress on Jessamine Lane near Hazelwood Street, said Steve Linders, a St. Paul police spokesman.
The victim was taken to Regions Hospital.
Dyamond Richardson, Diamond Reynolds and Chnika Blair.
Reynolds, 27, was charged in Ramsey County with two felony counts of assault.
Charges are expected to be filed later Friday.
Reynolds gained global attention after her boyfriend, restaurant worker Philando Castile, was shot during a routine traffic stop, also in Ramsey County, near Minneapolis. Reynolds talked to the officer and described what happened on Facebook Live.
Castile, who had a permit for the weapon, can be seen slumped over and moaning on the video, while the officer holds a gun at his face.
Online court records do not list an attorney who could comment on Reynolds' behalf. Reynolds was in the front passenger seat and her then-4-year-old daughter was in the backseat when Yanez fired into the vehicle.
Yanez pleaded not guilty to manslaughter and will be tried in May. She said then that faith kept her going, particularly as it became increasingly hard to find work.