Leopoldo Luque responded to the launch of the investigation for involuntary manslaughter by saying he had done "everything he could, up to the impossible" for an "unmanageable" patient.
Prosecutors in San Isidro, near Buenos Aires, said they were investigating Luque, while Argentine television showed police raiding the doctor's surgery and home.
A statement from the prosecutors' office later said they had begun analysing material gathered and clarified that "no decisions have been made at the moment regarding the procedural situation of any person".
Daughters concerned about treatment
The probe was triggered by concerns raised by Maradona's daughters Dalma, Gianinna and Jana over the treatment he received for his heart condition at his home in Tigre, north of Buenos Aires, judicial sources said.
Maradona died of a heart attack on Wednesday aged 60, and was buried on Thursday at the Jardin de Paz cemetery on the outskirts of the Argentine capital.
"Our investigations are ongoing, we are talking to witnesses including members of the family," a source close to the San Isidro inquiry said.
"The clinic had recommended that he go elsewhere to be hospitalised, but the family decided otherwise. His daughters signed for him to be discharged from the hospital," said a family member.
Emotional news conference
Later in the day, Luque, who is no relation to Maradona's former Argentina team-mate of the same name, gave an emotional televised news conference.
"You want to know what I am responsible for?" the 39-year-old doctor asked between sobs. "For having loved him, for having taken care of him, for having extended his life, for having improved it to the end."
Maradona’s doctor, Leopold Luque, giving interviews on his motorcycle outside the hospital is somehow very fitting. ☺️ #FuerzaDiego pic.twitter.com/a95vhseUnS
— Everything Napoli (@NapoliAndNaples) November 11, 2020
Luque said he did "everything he could, up to the impossible" and considered himself a "friend" of Maradona and saw him "as a father, not as a patient".
Luque had posted a photograph of himself with Maradona when the former player left hospital on 12 November, eight days after the doctor operated to remove a brain blood clot. Maradona returned home to Tigre where he received round-the-clock medical care and could remain close to his daughters.
"He should have gone to a rehabilitation centre. He didn't want to," said Luque who called Maradona "unmanageable".
