The Civil Guard had previously said a tyre had probably blown out while the vehicle was overtaking, causing it to crash and burst into flames.
“All the tests conducted so far indicate that the driver of the vehicle was Diogo Jota,” the force added.
Just hours before the accident, Jota had posted a video of his June 22 wedding to partner Rute Cardoso, with whom he had three children.
Portuguese and UK media reported Jota was driving to the northern Spanish port of Santander to take a ferry to England for the start of Liverpool’s pre-season training, avoiding a flight on medical advice after a recent lung operation.
Political leaders as well as star players from Portugal and Liverpool joined family and friends at the funeral on Saturday in the Porto suburb of Gondomar.
A site of remembrance has been set up at Liverpool’s Anfield stadium where fans and former players have laid a sea of flowers, shirts, scarves and pictures.
Fan favourite
Following spells at Atletico Madrid, Porto and Wolverhampton Wanderers, Jota became a fan favourite at Liverpool after joining the Premier League giants in 2020.
He netted 65 times for the Reds in five seasons, lifting the League Cup and FA Cup in 2021/22 and helping them win a record-equalling 20th English league title last season.
The striker also earned 49 caps for Portugal and was part of the team that won this year’s UEFA Nations League.
Younger brother Andre played in midfield for FC Penafiel in Portugal’s second tier.
Liverpool returned to training on Tuesday for the first time since Jota’s death, having postponed the start of their pre-season preparations last week.
Ticket sales for a friendly against Preston North End have been suspended pending a final decision on whether the match will go ahead.