Wednesday morning, police are revealing new details about what happened during last week's mass shooting in Ohio.

Officials are still trying to determine what prompted the shooter in Dayton, who killed nine people, on August 4. 

Tuesday, police said they used surveillance video to lay out a timeline of the movements of that gunman.

Officers said the primary focus in the investigation is the gunman's sister. 

Police said Megan Betts was one of the first victims that night. 

Police said the 22-year-old was shot and killed while she and a friend stood near a taco stand. 

However, police said they can not confirm that the shooter knowingly targeted her as he fired shots down an alley. 

later today, friend of the gunman is due in court. 

Investigators said Ethan Kollie bought body armor for Betts and helped assemble his weapon.

But, officials said Kollie is not accused of taking part in the shooting.

Dayton Police ALSO updated the number of people hurt-- saying now that in addition to the nine people killed-- 17 were injured by gunfire.