U.S. investigators study Brown University shooter's history

A quarter of a century ago, Claudio Neves Valente was briefly enrolled as a young, promising doctoral student in the physics department at Brown University before dropping out of the school in Rhode Island.



On Friday, police were still trying to figure out why Valente returned to the Ivy League school nearly a week ago, armed with at least one handgun.



He killed two students and injured several others before fleeing from the building where he once studied.



Searching for a motive, investigators were examining Valente's earliest days in academia, which took him from the University of Lisbon to the U.S. Northeast.

Two days into the manhunt for the Brown University attacker, a physics professor at the Massachusetts Institute of Technology was fatally shot in his home outside Boston:



Nuno Loureiro, who had been Valente's classmate as physics students at Lisbon's elite Instituto Superior Técnico in their native Portugal in the late 1990s.