Police are releasing a man detained in connection with the fatal shooting on the campus of Brown University in Providence, Rhode Island.
Two people were killed and nine others, all or nearly all of whom are also believed to be students, were injured in the attack on Saturday.
Earlier, three senior law enforcement officials briefed on the investigation told Sky’s US partner NBC News the detained man, who is being released, was 24-year-old Benjamin Erickson, who had served several years in the US army.
The release means that the suspected gunman remains at large.
Speaking at a news conference, Providence mayor Brett Smiley said: “We know that this is likely to cause fresh anxiety for our community and we want to reiterate what we said earlier… which is ever since the initial call, now a day and a half ago, we have not received any credible or specific threats to the Providence community.
“So the status of safety in our community remains unchanged, and we believe that you remain safe in our community.”
Mr Smiley said there would be a continuation of an enhanced police presence throughout the city and on the university campus.
“We have not yet solved this case, but I am confident we are going to do that in the near future,” Rhode Island attorney general Peter Neronha said.
The shooting happened inside a classroom on the first floor of the Barus & Holley engineering building, a seven-storey structure home to much of the university’s engineering and physics study and research.
Brown University provost Frank Doyle confirmed final exams were taking place in the engineering building when the gunman opened fire.
A police official told the AP news agency the gunman fired more than 40 9mm rounds. A gun has not been recovered, but officers did seize two loaded 30-round magazines.
A video released by officials shows a suspect walking down a street away from the campus and turning a corner, dressed in dark, loose-fitting clothing.
Seven people injured in the shooting were in a stable condition, the Providence mayor, Mr Smiley, said. One remained in critical but stable condition, while another had been discharged, he added.
Brown is a private university with roughly 7,300 undergraduate students and more than 3,000 graduate students.
