Police arrested seven men on Tuesday over separate alleged racist incidents against Real Madrid’s star winger Vinicius Jr.
Four men were arrested in Madrid, meanwhile the remaining were detained in Valencia.
Earlier, Vinicius had said La Liga "belongs to racists" after suffering vile abuse during Sunday’s clash at Valencia.
The 22-year-old Brazilian also identified the person hurling racist insults in the crowd during the second half. The match was delayed for several minutes due to the incident.
A hate crime investigation was also opened after an inflatable effigy, wearing Vinicius Jr’s jersey, was hung from a bridge in front of the club's training grounds in January.
"It was not the first time, not the second and not the third. Racism is normal in La Liga. The competition thinks it´s normal, the (Spanish) Federation also thinks it´s normal and opponents encourage it," Vinicius wrote on Instagram on Sunday.
"The league that once belonged to Ronaldinho, Ronaldo, Cristiano (Ronaldo) and (Leo) Messi, now belongs to racists.
"A beautiful nation, which welcomed me and which I love, but one which has agreed to export the image of a racist country to the world.
"I´m sorry for the Spaniards who don´t agree, but today, in Brazil, Spain is known as a country of racists. Unfortunately, for everything that happens every week, I have no way of defending it. I agree."
La Liga said they were investigating what happened and will take legal action, if necessary, against the perpetrators.
"La Liga has filed complaints (to relevant authorities) on nine occasions in the last two seasons," said the top flight in a statement.
"La Liga has been fighting against this kind of behaviour for years and promoting the positive values of sport, not only on the pitch but also off it."
Real Madrid coach Carlo Ancelotti also expressed his disappointment over the unfortunate incident.
"The Spanish league has a problem, and Vinicius is not the problem. Vinicius is the victim. There´s a very serious problem," Ancelotti said, adding that Vinicius was "sad, not angry" after the incidents at Mestalla.
Vinicius also received a straight red in injury time towards the end of the match for hitting Hugo Duro during a brawl.
"The fact I thought about taking him off because of the racist atmosphere does not seem good to me," Ancelotti told reporters.
"What has happened today has happened before, but not like that, it´s unacceptable."