The manhunt for the gunman who killed two students and wounded nine in a shooting at Brown University entered its fifth day on Wednesday after police in Providence, Rhode Island, released a new image and what they described as "enhanced" videos of a person of interest the case.

In several zoomed-in videos that police said were captured on the East Side of Providence on Saturday afternoon, approximately two hours before the shooting, the person of interest is seen walking on a sidewalk and looking around. The person is wearing a face covering. 

Some of the footage released Tuesday by the Providence Police Department on social media appeared to be digitally enhanced versions of previously released videos. Police urged anyone with information to contact the FBI tip line online or at 401-272-3121.

"Even small details may be critical to this," police said.

An image released earlier Tuesday, though blurry, was the clearest picture of the person of interest released so far since the shooting on Saturday. The FBI said the man is about 5-foot-8 with a stocky build. 

The FBI also shared a timeline of when the videos were captured, including some videos that appear to have been obtained from residents' private cameras. The person of interest is seen from about 2 p.m. on Saturday until just after 4 p.m., around the time the shooting took place.

Police said the individual was walking near Hope and Benevolent streets, just down the block from the Barus & Holley engineering building where the gunman opened fire. Authorities said Monday they had no information about a motive at this point.

The bureau has offered a $50,000 reward for information leading to the identification, arrest and conviction of the gunman.

Rhode Island Attorney General Peter Neronha said investigators have also obtained other videos that have not been released to the public.

"I want to be clear because later on there may be other videos that get released in the course of a prosecution. … They show things like chaos after the shooting. What they don't show is this person of interest," Neronha said at a news conference Tuesday.

Amid growing questions about campus security measures and the lack of better surveillance video, the university released a statement Wednesday saying that while Brown has "an expansive network of security cameras," the cameras "do not extend to every hallway, classroom, laboratory and office across the 250+ buildings on campus."

"Brown has heightened security on campus considerably in recent days, and we will do a large-scale systematic security review of the entire campus. We know we live in a different time," the statement said.

Investigators say they are looking to interview anyone who was in the area of the shooting. They're also continuing to search the area for evidence that might lead to the gunman.

Rhode Island Hospital provided an update Tuesday about the conditions of the victims who were wounded, saying two have been released from the hospital, while five are in critical stable condition, one is in critical condition and one is stable.

The two students killed in the attack were identified as Ella Cook, a sophomore from Alabama, and Mukhammad Aziz Umurzokov, an Uzbek American freshman.

"Both were brilliant and beloved — as members of our campus community, but even more by their friends and families," Brown's president, Christina H. Paxson, wrote in a letter Tuesday to the university community. "Our hearts continue to be with them in their profound sorrow."

Meanwhile, Brown University says it has seen an increase in swatting calls since the shooting. The community has seen increased security presence, with restrictions to buildings and areas, but students say it will take effort and time for them to feel safe. 

"We were in a state where Brown felt incredibly safe, and that bubble of safeness was completely popped when we were violated by a shooter entering our campus," Talia Levine, a senior at Brown University who barricaded for four hours during the shooting, told CBS News.

At a news conference on Tuesday, Paxson said she has been "deeply saddened" to see people questioning the university's commitment to safety and security. 

"I understand that as time goes on, there is maybe a natural instinct to assign responsibility for a tragic event like this. Anxiety and fear is very natural. But the shooter is responsible," Paxson said. "Horrific gun violence took the lives of these students and hospitalized others and it's deeply sad and tragic that schools across the country are targets of violence, and Brown is no exception."