In the ongoing search for the suspect involved in the Brown University shooting, newly released surveillance footage reveals a masked individual displaying behavior that shifts from collected to visibly uneasy. This change in demeanor, highlighted by a body language expert, suggests typical “anomalies” associated with individuals having harmful intentions.

Susan Constantine, a licensed authority in threat-assessment behavior, explained to Fox News Digital that specific actions, like the suspect’s wandering gaze, pacing, and hands clasped behind their back, are indicative of loitering behaviors rather than simply moving through an area. “These are consistent with anomalies observed in those with malicious intent,” Constantine noted.

In the initial segments of the video, captured before the shooting, Constantine remarked that the suspect appeared to have a clear objective. “He seems to be in the midst of a reconnaissance or rehearsal,” she commented, suggesting that the individual might have been planning routes or assessing the placement of CCTV cameras.

The footage includes a series of still images, captured near Brown University, showing the suspect both before and after the incident. Constantine identified these moments as significant, offering vital clues that could aid in identifying the person of interest. According to the FBI in Boston, these frames are pivotal in piecing together the suspect’s movements and intentions prior to the attack.

A split image showing multiple still frames from the surveillance video taken near Brown University of a person of interest before and after a school shooting Saturday. Constantine flagged these specific moments as showing key markers that can help identify the person of interest. (FBI Boston)

But he soon raised red flags and displayed “a really important marker” showing the unique way that he walks, she said.

“When crossing the street in the middle of the block, the subject’s pace quickens, and he seems to be in a hurry. His gait becomes hurried, and a more waddling gait can be seen. He has his right hand in his pocket. It is not possible to determine if he has a weapon or not, but concealing the hand and object within it inside a pocket is a form of concealment. The subject’s right lower leg also bows outward as he walks, resulting in an abnormal gait.”

WATCH: Surveillance videos show person of interest in Brown University shooting

The Brown University shooting person of interest running in a still frame taken from video. Constantine said this image makes it appear as though the person of interest is not as stocky as initially viewed. (FBI Boston)

Police in Providence, Rhode Island, have released multiple video clips and other surveillance images in the hope that members of the public can help identify the person of interest, who remains at large more than 72 hours after a mass shooting in a lecture hall Saturday.

FBI Boston released a timeline of surveillance camera footage that captures a person of interest in the Brown University shooting. (FBI Boston via X)

“Taken as a whole, the characteristics of a heavy or stocky build, behavioral changes, hyper awareness of surroundings, pacing movements, bulky clothing, facial and hand concealment, and a hurried pace with a waddle as he walks and his right lower leg bowing out as he walks are characteristics that could be used to track this person in the future,” Constantine said.

FBI Boston released a timeline of surveillance camera footage that captures a person of interest in the Brown University shooting. (FBI Boston via X)

In particular, she said the videos show his right leg bowing inward while his toe points outward as he walks. And he could be right-handed, she said, based on how he walks with one hand in his pocket and the other swinging freely.

FBI Boston released a timeline of surveillance camera footage that captures a person of interest in the Brown University shooting. (FBI Boston via X)

“These are behavior traits that cannot be controlled,” she explained. “That’s what’s causing him to waddle. Could be a knee injury.”

The attack left two students dead, identified as Ella Cook of Alabama and Mukhammad Aziz Umurzokov of Virginia, and nine injured.

FBI Boston released a timeline of surveillance camera footage that captures a person of interest in the Brown University shooting. (FBI Boston via X)

Authorities said during a Monday news briefing that they recovered 9mm casings at the scene.

Police released additional surveillance clips Tuesday afternoon, one of which showed the purported person of interest walking right by officers as they responded moments after the shooting. The additional footage, in higher resolution, shows the person is not as stocky as initially expected, Constantine said, especially during a portion where he is seen running along a picket fence.

“He is concealing something under his jacket,” she said. “He is not as stocky as first viewed.”

The gunman remains at large.

Anyone with information is asked to call Providence police at 401-272-3121 or submit tips to the FBI online.