(NEWTOWN, Conn.) -- A Newtown, Conn., priest had the "horrible" job of going door-to-door informing families early Saturday morning that their children had been killed in the elementary school massacre.
There were 20 children among the 27 people killed the day Adam Lanza, 20, invaded Sandy Hook Elementary School and opened fire on staff and students. Lanza was also found dead in the school.
Most of the children were between the ages of 5 and 10, President Obama said on Friday.
Medical examiners have completed the grim work of identifying all of the victims at the school and families were informed early on Saturday morning that their loved ones had been killed.
"We were gathered until after midnight and we were sent out with teams to go to the homes of the victims," parish priest Monsignor Robert Weiss told Good Morning America on Saturday. "We went to their homes early this morning to confirm the death of their children and it was just horrible."
"The uncertainty...even though they knew in their hearts that this was real," he said. "And the questions they were asking, the regrets they had. 'Why did I send my child to school today?'"
Weiss said some of the parents shared the last moments they had with their children. One dad said that, for some reason, his child got up early Friday morning and came down to tell the father how much she loved him. Another parent said their child had asked what dying was like just the day before.
"Parents are really going through a tremendous amount of pain and hurt right now, trying to deal with not just their personal loss, but what happened to their child in the last moments of their life," he said.
A number of the victims' families are part of Weiss' parish. He baptized some of the children and some of them went to his parish's nursery school.
"It's hard to believe that these little children are gone," he said.
Weiss met with the families from his parish who lost children and said the hurt and the anguish are "just settling in now" and then "there's going to be anger."
"And then they're going to have to live with this reality that this big part of their life is gone for them," he said.
Weiss said he has "no answer" when families ask him why their children have been taken from them.
"This was not God's plan," he said. "This was a man who has serious issues in his life. Why he'd want to destroy innocent children, no one can figure out."
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