A person of interest detained after a Brown University shooting that killed two students and injured nine will be released after law enforcement authorities determined there was no basis to keep the individual in custody, officials said on Sunday night.

The disclosure, made at a hastily convened late-night news conference, represents a dramatic setback in an investigation into killings that set off hours of chaos on the Ivy League campus and unravels progress that authorities thought they had made earlier in the day when they detained a man at a Rhode Island hotel in connection with the attack.

United States news media outlets, including The Washington Post and NBC News, cited unnamed sources identifying the man as 24-year-old Benjamin Erickson, who previously resided in Wisconsin.

A person by the name of Benjamin W. Erickson served as a US Army infantryman from May 2021 to November 2024, leaving the service with the rank of specialist without ever being deployed, military officials told Reuters. However, they could not confirm whether he was the man detained over the Brown University shooting.

The release of the lone person of interest leaves law enforcement without any known suspect, with officials pledging to redouble efforts in the investigation by canvassing for video surveillance that could help pinpoint the killer's identity.

"We're in the process of collecting evidence and seizing items that we need to seize, search locations that we need to search," said Oscar Perez, police chief in Providence, Rhode Island, where the university is located.

President Donald Trump called the shooting "a terrible thing" and sent his "deepest regards and respect" to the bereaved families. He told the nine survivors to "get well fast".

Providence Mayor Brett Smiley said the shooting took place at the Barus and Holley building, which houses classrooms and laboratory space for the engineering and physics departments. A law enforcement official told The Associated Press that the gunman opened fire inside a classroom in the engineering building, firing more than 40 rounds from a 9 mm handgun.

The shooting happened around 4 pm on Saturday as students prepared for final exams. Brown University canceled all remaining classes, exams, papers and projects for the semester.

On Sunday evening, city leaders, residents and others gathered at a park to honor the victims. The event was originally scheduled as a Christmas tree and Hanukkah menorah lighting.

"For those who know at least a bit of the Hanukkah story, it is quite clear that if we can come together as a community to shine a little bit of light tonight, there's nothing better that we can be doing," Smiley said.

Agencies contributed to this story.

shiguang@chinadailyusa.com