Spain's La Liga on Monday said it was reviewing a video of a child making racist insults towards Real Madrid forward Vinicius Junior during the 2-2 draw with Valencia at the weekend.
"We're in the process of studying and analysing the facts from a legal standpoint to see what we can and should do," La Liga sources said.
In a video published by a journalist for ESPN Brasil, and picked up by Spanish media, a boy sitting in a woman's lap can be heard calling Vinicius a "monkey".
The Brazilian scored twice for Madrid as his team recovered from two goals down at Mestalla on Saturday.
Vinicius raised his fist in a "Black Power" salute after the first of his two goals at a ground where he was racially abused last season. Valencia subsequently banned three people from the stadium for life.
The 23-year-old has become a symbol of the fight against discrimination in Spanish football after suffering racist abuse on many occasions, and he was jeered repeatedly by home supporters on Saturday.
Jude Bellingham was sent off after the final whistle against Valencia for protesting after the referee blew the final whistle right before the England midfielder headed home what he thought was the winning goal.
