BREAKING: Authorities recover unused ammo from Brown shooting scene: report

Mauro said that even if the suspected shooter’s DNA is not in the system, authorities could use familial DNA to track down a relative and work back from there.

Since Saturday's shooting, which saw the deaths of two students, Ella Cook and Mukhammad Aziz Umurzokov, and nine others injured, the suspected gunman has not been taken into custody. Authorities have urged the public to submit any footage they may have from home security cameras and cars of the suspect in the area.

In a Wednesday press conference, Providence Police Chief Oscar Perez said that authorities "have both seized and found physical evidence." Authorities have said there is currently "zero information" regarding motive in the case, and that the gunman responsible "could be anywhere."

Authorities have released multiple images and video of the suspect walking in the area of Brown University, and have said that the suspect was in the area prior to the shooting casing it out. Police have also released images of a person of interest they want to speak to who was seen "in proximity" of the suspect.