Baltimore County State's Attorney Scott Shellenberger will sit down with her family on Wednesday to explain the outcome of their investigation. Attorneys for the family will hold a press conference on Wednesday.
23-year-old Gaines was killed after an 6-hour-long standoff with Baltimore County Police on August 1.
Last week Gaines' estate filed a lawsuit citing their lack of trust in the police's investigation.
Police say they fired at Gaines' after she verbally threatened them, but the family's lawyer disagrees
"He did not shoot her because he was in fear that she posed a threat to him or other officers. They had been with Ms. Gaines for approximately seven hours. He shot Ms. Gaines out of frustration, and that is not a legitimate basis for shooting and killing an individual," Attorney J. Wyndal Gordon said.