BROOKLINE, Massachusetts: Authorities launched a homicide investigation into the fatal shooting of a professor from the Massachusetts Institute of Technology at his home near Boston on December 15.

Nuno F.G. Loureiro, a 47-year-old physicist and fusion scientist who was shot at his home in Brookline, Massachusetts, died at a local hospital the next day, the Norfolk District Attorney's Office said in a statement.

Investigations were ongoing, and no suspects had been taken into custody as of the afternoon of December 16.

Loureiro joined MIT in 2016 and was named last year to lead MIT's Plasma Science and Fusion Center, where he aimed to advance clean energy technology and other research.

Loureiro, who was married, 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, it 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.

MIT President Sally Kornbluth stated that Loureiro's death was a "shocking loss."

Loureiro's murder in Brookline comes on the heels of the killing of two students at Brown University on December 13. Police in Providence, Rhode Island, are still searching for the gunman, who left nine others injured. The FBI said it knew of no connection between the two crimes.

A 22-year-old student at Boston University who lives near Loureiro's apartment in Brookline told The Boston Globe she heard three loud noises on the evening of December 15 and feared it was gunfire. "I had never heard anything so loud, so I assumed they were gunshots," Liv Schachner was quoted as saying. "It's difficult to grasp. It just seems like it keeps happening."

Some of Loureiro's students visited his home to pay their respects, the Globe reported.

In an online post, the U.S. ambassador to Portugal, John J. Arrigo, offered his condolences and honored Loureiro for his leadership and contributions to science.

"Fusion energy will change the course of human history," Loureiro had said when he was asked to lead the plasma science laboratory last year. "It's not hyperbole to say MIT is where you go to find solutions to humanity's biggest problems."