According to a police statement today, the suspect said he was motivated by jealousy for the children, aged 4 and 8, because older family members gave them more attention.
Tuesday's deaths at the southern village of Strefi, near Ancient Olympia in the Peloponnese region, were initially treated as accidental. But police noticed that one of the dead boys was still clutching a shirt, which was found to belong to the suspect.
The younger boy is believed to have torn the shirt off his uncle as he was being pushed.