Two young men were stabbed at a Tufts University fraternity house in what was apparently not a random attack.

Tufts issued an emergency announcement Sunday, alerting the campus of the attack early that morning and encouraging people to stay wherever they are. Local and university police later swept the area and determined there was not ongoing threat.

The Somerville Police interviewed a Tufts student they considered a "person of interest" in the attack that left a 20- and 19-year old hospitalized, the Boston Globe reported.

The older of the two was in serious condition after doctors at Massachusetts General Hospital performed surgery. The 19-year-old was released later in the day Sunday. Neither was a student at Tufts, but both were among six people who lived in the house.

Police believe the victims knew their attacker and that three of the house's six occupants were not there at the time of the attack.

According to the Associated Press, police arrived at the Tufts Delta Tau Delta house around 4 a.m. to find the two men bleeding, but conscious. They were outside when the officers arrived, but the stabbing likely occurred inside.

The fraternity's national office confirmed it would be assisting in the investigation in any way it can.

"At this time our thoughts are focused on the speedy recovery of the injured parties," Jim Russell, Delta Tau Delta's national executive vice president, told the AP.

Tufts' shelter-in-place order was lifted by 8 a.m. Sunday morning, but the school said it would leave police officers at the scene.

Michael Miele, a 22-year-old who lives close to the fraternity house, told the Globe there did not appear to be a party or much activity at all. He said he returned home at 3 a.m. Sunday morning and spent some time outside. The surrounding neighborhood reportedly has a reputation for being safe and quiet.

"If there was a party, it would have been much louder," Miele said. "But there was no noise, no yelling, nothing.

"It was pretty apparent something bad had gone on, so we went inside, made sure the doors were locked, and went to bed."