"Widnes Vikings will of course be looking to celebrate Kato's life and pay our sincere respects to someone who we believe would have become a hero at our Club.
"Whilst we are coming to terms with this news, and still learning the full facts of this situation, we are unable to comment further at this time."
Denis Betts, Head Coach of Widnes Vikings, said: "To receive this tragic news is heart-breaking. All of us saw at the World Cup the incredible gifts that Kato had, and his potential to forge a great career in Rugby League. Moreover, in all of our interactions with him, we found Kato to be a person of great character, who was excited to be following his dreams. On behalf of the coaching team, staff and players at Widnes Vikings, I would like to offer our sincere condolences to Kato's loved ones."
Although he never got to make his NRL debut for the Raiders, Ottio was a prolific try scorer for Canberra's feeder side Mounties in the NSW Cup.
Raiders teammates this morning took to social media to pay tribute to Ottio.
Raiders forward Elliott Whitehead said Ottio would be sorely missed.
"Such sad news this morning hearing about Kato passing away," Elliott said on Instagram. "One guy who has always had a smile on his face. Loved my time with him at Raiders. RIP mate, gone way to soon."
Blake Austin echoed the sentiments of his teammates.
"Shattered to hear the news about Katsy. Wasn't a day he wasn't smiling, gone way too soon. Prayers with all his family," Austin posted to his Instagram account.
Tributes weren't limited to Raiders teammates, with players from rugby league's international community also honouring their mate.
Ottio left the Raiders at the end of the 2017 season to take up a Super League contract with Widnes Vikings.