As police continue their search for a suspect accused of opening fire at Brown University, killing at least two people and wounding nine others, a law enforcement expert is emphasizing that early information is often incomplete or conflicting and that officers must verify information before acting.

“Facts in situations like this often change, sometimes rapidly,” said retired FBI Supervisory Special Agent Jason Pack, who has 21 years of service. “Early information comes from multiple sources, often under stress, and law enforcement has to verify each piece before acting on it or releasing it publicly.

“At the same time, officers are doing some of the most difficult work in policing right now, which is clearing buildings that are on lockdown.”

He added that law enforcement’s efforts are “slow, deliberate and dangerous work.”

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“Every hallway, every stairwell, every classroom and office has to be treated as a potential threat until it’s cleared,” he said.

An unidentified male gunman was last seen leaving the Barus & Holley engineering building at the prestigious Rhode Island university after the shooting at about 4 p.m.

Multiple local law enforcement agencies, along with the FBI and U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) are investigating. Officials have said the alleged shooter was dressed in black.

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Pack said officers are “moving methodically, often in low light, with limited information and with the understanding that someone inside those buildings may be frightened, hiding or unable to communicate clearly.”

“That requires discipline and restraint, not speed,” he said, adding that the search may extend into Sunday. “This is why timelines stretch and why you may hear updates that evolve over the night. Law enforcement is balancing two responsibilities at once — moving fast enough to protect lives but slow enough to make sure nothing is missed.”

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Pack said law enforcement’s goal is “simple but not easy.”

“Make sure every space is safe, every person is accounted for and that the threat is fully resolved before restrictions are lifted,” he said.