The victim has been identified as Andrea Rebello of Westchester County.
The shots rang out inside an off-campus house on California Avenue just after 2:30 a.m.
Police responded to a report of a home invasion robbery in a house where three female students and one male student live. Authorities say the incident began when an armed man with a black ski mask forced his way inside.
One of the victims was permitted to leave the home, apparently to withdraw money from an ATM, and she called 911.
Somehow, gunfire erupted after police arrived. One responding officer said the scene resemebed a hostage situation, with the suspect pointing a gun at the heads of his victims.
Rebello, and the suspect, who police say was not a student, were both killed.
It is unclear who fired the fatal shots.
No police officers were injured in the gunfire.
Police closed a large number of streets surrounding the home, just down the street from the Hofstra University campus, as they investigate.
The incident happened on the last day of finals, as students were looking forward to graduation week.
A private vigil held at the Hofstra Student Center brought together grief counselors and Andrea Rebello's sorority sisters and friends.
Joe Moncada was the 21-year-old's resident assistant in 2012. He says that on Friday there were a lot of tears. Espescially from Rebello's sorority sisters.