The shooter is 24-year-old Ryan Lanza, NBC confirms. He was one of the dead at Sandy Hook Elementary.
Tweets from December include "I would actually love if the world ended in 2 weeks," "the feeling when you know youve lost everyone who used too care about you," "i want my bestfriend back.. why did everything have to change... again."
NBC says his father was shot to death at his home in New Jersey, and that his mother worked at Sandy Hook Elementary School.
WNBC: Ryan Lanza began shootings at the Sandy Hook Elementary School office, then went to his mother's kindergarten class, where he killed her.
WNBC anchor: "24-year-old Ryan Lanza wrote his name in blood in the Connecticut history books this morning."
WNBC: There will be a vigil for the victims at 7 p.m. at a church in Newtown.
Heading back to the second press conference now. Gov. Malloy's set speak with reporters at 3:30.
The suspect's father lives in Hoboken, NJ, his mother in Newtown. Both are feared dead.
WNBC: A statement from President Obama is expected at 3:15 p.m.
Correction: The tweets posted earlier attributed to Ryan Lanza appear to have been written by a different person with the same name.
WNBC: An additional relative of Ryan Lanza's has been found dead in a home in Newtown, Conn. So that's his father in Hoboken, another relative in Newtown, his mother at Sandy Hook Elementary School, and additionally his brother being held by police.
President Obama is expected to make a statement about the school shooting in the next few minutes.
President Obama speaking now.
"I made it clear that he will have every resource he needs to investigate this heinous crime, care for the victims, counsel the families."
"I know there's not a parent in America who doesn't feel the same overwhelming grief that I do. The majority of those who died today were children -- beautiful little kids between the ages of 5 and 10 years old."
He has had to pause to compose himself twice.
"Our hearts are broken today for the parents and grandparents, sisters and brothers of these little children, and for the families of the adults who were lost."
"As a country we have been through this too many times, whether it's an elementary school in Newton, or a mall in Oregon, or a temple in Wisconsin or a street corner in Chicago."
"In the hard days to come, that community needs us to be at our best as Americans, and I will do everything that I can as president to help. ... All of us can extend a hand to those in need, to remind them that we are there for them, that we are praying for them."
"In the words of scripture, 'heal the broken hearted and bind up their wounds.' "
WNBC: Ryan Lanza's girlfriend and another friend are missing in New Jersey.