"He was just this scrawny little kid who was always giggling and happy, " said Juliette Terry, 20, who met Dzhokhar in elementary school and was part of a group of friends with whom he attended prom.

WSJ: Boston Marathon Bombings: Turn to Religion Split Bomb Suspects Tamerlan and Dzhokhar Tsarnaev's Home

Once a rare break from restrictive rules governing the behaviour of rural young women who were not allowed to sing aloud or go out at night, except during the Chuseok Thanksgiving celebration, the ritual is mostly preserved today by middle-aged women in cities and taught as part of the music curriculum of elementary schools.

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Neighbor Gina McDade said Nancy Lanza was a "stay-at-home mom" and not a teacher or part-time employee of Sandy Hook Elementary, as some media reports stated.

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Part of the building was transformed to resemble an elementary school, and security was increased by adding new locks and surveillance cameras, a school official has said.

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For his part, the President helped to refurbish a Washington, DC elementary school, applying some varnish to a classroom bookshelf.

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Newtown Public Schools Superintendent Janet Robinson has said that part of the Chalk Hill building had been transformed to resemble an elementary school and that security had also been increased, incorporating an upgraded system of new cameras and locks.

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