Investigators think there could be a link between the campus mass shooting at Brown University and the MIT professor who was later killed at his home — and law enforcement is now digging into a possible connection, TMZ has learned.

A federal law enforcement source tells TMZ … federal, state and local authorities are now looking into whether the fields of physics and engineering are a factor in the murders linking the two cases. No suspects have been identified or apprehended in either case.

This is a major shift in the investigation — especially since FBI Boston Special Agent in Charge Ted Docks said Tuesday there didn’t appear to be any connection between the two shootings.

The violence kicked off Saturday, Dec. 13, when a gunman went on a rampage at Brown University in Providence, Rhode Island, in the Barus and Holley building, which houses School of Engineering and the Physics Department — killing two students and injuring nine others. Providence Police have released enhanced video of a new person of interest tied to the campus shooting.

On Monday, Dec. 15, Massachusetts Institute of Technology professor Nuno F. Gomes Loureiro was gunned down at his home in Brookline, Massachusetts shortly before 8:30 PM Monday. The MIT professor worked in the Nuclear Science and Engineering Department.

Brookline is 50 miles north of Providence.