Latest developments of worst U.S. mass shooting

The following are some latest developments of shooting rampage in which at least 33 were killed at Virginia Tech at Blacksburg, Va., Monday morning, based on U.S. media reports.

-- U.S. President George W. Bush's staff has talked to Virginia Tech officials about the possibility of Bush's visit to the campus this week, Tech President Charles Steger said at a press conference Monday evening.

-- Authorities said they have identified a "person of interest" but do not have anyone in custody. That person is cooperating with authorities, they said.

-- Va. Tech police Chief Wendell Flinchum said that an estimated 15 people have been injured from the shooting.

-- Flinchum said police had made a preliminary identification of the shooter but were not releasing the identity. He also said that two weapons were recovered but declined to say what they were.

-- Norris Hall, where 31 of Monday's 33 victims died and 15 more were injured, is a crime investigation scene on Monday night.

-- A long piece of yellow police tape is tangled in a tree and federal Bureau of Alcohol, Tobacco, Firearms and Explosives agents seemed to be looking through windows of cars parked in the campus. No vehicles are being allowed onto campus.

-- "Hokies United," an ad hoc group that has brought together Virginia Tech's student organizations during past tragedies, is organizing a candlelight vigil Tuesday night.

-- Virginia Governor Tim Kaine has declared a state of emergency.

-- Va. Tech students have started a facebook site titled "I'm ok at VT" to let each other know their whereabouts and ask about people who are missing.