PROVIDENCE, R.I. (AP) — Authorities said Thursday that they're looking into a connection between last weekend's mass shooting at Brown University and an attack two days later near Boston that killed a professor at another elite school, the Massachusetts Institute of Technology.

That is according to three people familiar with the matter who were not authorized to discuss an ongoing investigation and spoke on condition of anonymity. Two of the people said investigators had identified a person of interest in the shootings and were actively seeking that individual.

The attacker at Brown on Saturday killed two students and wounded nine others in a classroom in the school's engineering building before getting away.

About 50 miles (80 kilometers) north, MIT professor Nuno F.G. Loureiro was gunned down in his home Monday night in the Boston suburb of Brookline. The 47-year-old physicist and fusion scientist died at a hospital the next day.

The FBI previously said it knew of no links between the cases.

How is the Brown investigation going?

It's been nearly a week since the shooting at Brown. There have been other high-profile attacks in which it took days or longer to make an arrest, including in the brazen New York City sidewalk killing of UnitedHealthcare's CEO last year, which took five days.

But frustration is mounting in Providence that the person behind the attack managed to get away and that a clear image of their face has yet to emerge.

“There’s no discouragement among people who understand that not every case can be solved quickly,” the state attorney general, Peter Neronha, said at a news conference Wednesday.

Authorities have scoured the area for evidence and pleaded with the public to check any phone or security footage they might have from the week before the attack, believing the shooter might have cased the scene ahead of time.

Investigators have released several videos from the hours and minutes before and after the shooting that show a person who, according to police, matches witnesses' description of the shooter. In the clips, the person is standing, walking and even running along streets just off campus, but always with a mask on or their head turned.

Although Brown officials say there are 1,200 cameras on campus, the attack happened in an older part of the engineering building that has few, if any, cameras. And investigators believe the shooter entered and left through a door that faces a residential street bordering campus, which might explain why the cameras Brown does have didn’t capture footage of the person.

Providence Mayor Brett Smiley said Wednesday that the city is doing “everything possible” to keep residents safe. However, he acknowledged that it is “a scary time in the city” and that families likely were having tough conversations about whether to stay in town over the holidays.

“We are doing everything we can to reassure folks, to provide comfort, and that is the best answer I can give to that difficult question,” Smiley said when asked if the city was safe.

What can be learned from past investigations?

Although it’s not unheard of for someone to disappear after carrying out such a high-profile shooting, it is rare.

In such targeted and highly public attacks, the shooters typically kill themselves or are killed or arrested by police, said Katherine Schweit, a retired FBI agent and expert on mass shootings. When they do get away, searches can take time.

“The best they can do is what they do now, which is continue to press together all of the facts they have as fast as they can,” she said. “And, really, the best hope for solutions is going to come from the public.”

In the 2013 Boston Marathon bombing, it took investigators four days to catch up to the two brothers who carried it out. In a 2023 case, Army reservist Robert Card was found dead of an apparent suicide two days after he killed 18 people and wounded 13 others in Lewiston, Maine.

The man accused of killing conservative political figure Charlie Kirk in September turned himself in about a day and a half after the attack on Utah Valley University's campus. And Luigi Mangione, who has pleaded not guilty to murder charges in the killing of UnitedHealthcare CEO Brian Thompson in Manhattan last year, was arrested five days later at a McDonald's in Pennsylvania.

Felipe Rodriguez, a retired New York police detective sergeant and adjunct professor at the John Jay College of Criminal Justice, said it’s clear that shooters are learning from others who were caught.

“Most of the time an active shooter is going to go in, and he’s going to try to commit what we call maximum carnage, maximum damage,” Rodriguez said. “And at this point, they’re actually trying to get away. And they’re actually evading police with an effective methodology, which I haven’t seen before.”

Investigators have described the person they are seeking as about 5 feet, 8 inches (173 centimeters) tall and stocky. The attacker's motives remain a mystery, but authorities said Wednesday that none of the evidence suggests a specific person was being targeted.

MIT mourns the loss of an esteemed professor

Loureiro, who was married, joined MIT in 2016 and was named last year to lead the school's Plasma Science and Fusion Center, where he worked to advance clean energy technology and other research. The center, one of MIT's largest labs, had more than 250 people working across seven buildings when he took the helm. He was a professor of physics and nuclear science and engineering.

He grew up in Viseu, in central Portugal, and studied in Lisbon before earning a doctorate in London, according to MIT. He was a researcher at an institute for nuclear fusion in Lisbon before joining MIT, the university said.

“He shone a bright light as a mentor, friend, teacher, colleague and leader, and was universally admired for his articulate, compassionate manner,” Dennis Whyte, an engineering professor who previously led MIT’s Plasma Science and Fusion Center, told a campus publication.

Loureiro had said he hoped his work would shape the future.

“It’s not hyperbole to say MIT is where you go to find solutions to humanity’s biggest problems,” Loureiro said when he was named to lead the plasma science lab last year. “Fusion energy will change the course of human history.”

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This story was updated to delete a reference to MIT being an Ivy League school.

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Richer and Tucker reported from Washington. Associated Press reporters Mark Scolforo in Harrisburg, Pennsylvania, and Hallie Golden in Seattle contributed.