They appealed Thursday for the public’s help by releasing additional photos of the person they believe is responsible.

Utah Department of Public Safety Commissioner Beau Mason said a suspect who was taken into custody shortly after the shooting was released because he “was not an accurate person of interest.” However,

An at-large suspect dressed in all-black tactical gear fired a single shot at Utah Valley University, and Charlie Kirk later died of his injuries, officials said. Dispatch audio reviewed by PEOPLE included the suspect’s description.

Angela Fuller, 56, has been missing for two weeks. Anthony Reese, 56 is in custody the last person to have seen her.