Police raided a home in Barrancas, La Guajira, in the early hours of Wednesday where they captured a man suspected of participating in the kidnapping, Cambio reports.
The man in custody is believed to be the person who tracked Luis Diaz's parents and then informed the kidnappers of their movements.
Both of the player's parents were kidnapped on Saturday. While his mother, Cilenis Marulanda, was released hours later, his father, Luis Manuel Diaz, is still being held captive. Police have offered a 200 million peso (£40,000/$49,000) reward for information about the kidnapping.
Police suspected that the kidnappers would attempt to smuggle Luis Manuel Diaz into Venezuela, but the South American nation has said they have not made it over the border.
The incident has caused an uproar in Colombia, as Barrancas residents held a candle-lit march to demand the release of the kidnap victim.
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GettyParticipants of the march wore white t-shirts depicting a picture of Luis Manuel Diaz, who is said to be a popular figure in the town as he coaches young footballers.
“I feel a pain in my soul because I am a mother too and it is an injustice that a son of the people, a son of Barranquera and Colombian families, is in that sadness,” Alis Amaya, a citizen who attended the march, said to CaracolTV.
"They have taken the soul of a noble and simple person from us," said Miguel Cantillo, another person in attendance.