Washington: "It wasn`t me I was at work It wasn`t me", wrote Ryan Lanza on his Facebook page soon after he was mistakenly named as the man who shot dead 28 people, including 20 children, at a US school.
The shooter has been identified as 20-year-old Adam Lanza, the younger brother of Ryan Lanza.
The elementary school shooting left 20 children and 8 adults dead in the US state of Connecticut, the second deadliest in US history only next to the Virginia Tech Massacre in April 2007, which claimed 33 lives.
Ryan Lanza was working at his desk at the Ernst and Young when he saw a TV report that he had fatally shot people at the elementary school in Connecticut.
It was at that moment Ryan realized what his brother, Adam, might have done.
Lanza told his boss that: "I need to go."
He then walked out from Times Square office of the tax real-estate group, according to a co-worker who spoke to MailOnline on condition of anonymity.
Ryan stoutly defended himself in a series of Facebook posts after he was mistakenly named as the killer.
He wrote on his Facebook page: "I`m on the bus home now it wasn`t me."
Less than two minutes he wrote in capital letters: "IT WASN`T ME I WAS AT WORK IT WASN`T ME."
Ryan has been detained by the police.