The officer, from the 12th division, was transferred to Basurto hospital in Bilbao where doctors were able to revive him at first but ultimately, his heart stopped and he passed.
Over 2,000 ticketless Spartak Moscow fans were in Bilbao on Thursday night. The incidents outside the stadium began when the Russian fans threw glass bottles toward the areas where fans of Athletic Bilbao were situated, provoking a full on battle.
The ertzaina were left with no choice but to charge the ultras, to try to pacify them and arrest the worst offenders, of which there were at least five behaving like 'maniacs'.
This news comes on the same day that a Russian fan was arrested in Munich on charges brought against him following the England - Russia game in Marseille in 2016.
Throughout that tournament Russian fans developed a reputation for violence and cruelty that resulted in a suspended sentence being handed down, and a threat of disqualification from the tournament. After these clashes one Russian government official, Igor Lebedev said on Twitter: "I don't see what is wrong with the fighting, keep it up lads!"
Russia will be hosting the FIFA World Cup this summer.