Authorities are asking for video that people might have of the Brown University shooter in the days before the attack.

Investigators are seeking tips from the public, specifically video of the shooter possibly casing the area the week before the shooting, The Associated Press reported.

The shooting occurred on Saturday at Brown University, leaving two students dead and nine wounded.

Law enforcement has released several videos from the day of the attack, showing the suspected shooter on the streets just off campus. The person in the footage is wearing a mask or has their head turned.

“I believe that this is probably the most intense investigation going on right now in this nation,” Providence Police Chief Col. Oscar Perez said at a Wednesday news conference. He noted that witness accounts of the shooter match the person in the videos.

Brown University has 1,200 cameras on campus, but the attack was in an older building that has “fewer, if any” cameras, Rhode Island Attorney General Peter Neronha (D) said. Authorities believe the shooter used a door that faces a residential street.

According to investigators, the person they are seeking is about 5 feet, 8 inches tall and stocky, but they have not given any indication that they are close to determining their identity.

Perez said investigators have not found evidence to suggest that someone was targeted in the shooting.

Police on Wednesday released a new photo of another person who they said was in “proximity of the person of interest,” and asked the public to help identify that individual.

Perez declined to say how many witnesses police had spoken to or the number of people who were in the classroom during the attack. He said he is hoping more students with information will come forward.

However, many students have already left campus for the semester. The remaining classes and exams before winter break were canceled after the shooting.