Diego Maradona's doctor Leopoldo Luque says he did the best he could for the World Cup winner and is not responsible for his death, as police seized medical documents from him and searched his house.
Maradona died aged 60 on Wednesday of a heart attack in a house outside Buenos Aires where he had been recovering from a brain operation, with his burial taking place the next day.
Searches at Luque's home and office have been requested as part of an investigation into the death, according to a prosecutor statement.
The search order was requested on Sunday by prosecutors in the Buenos Aires suburb San Isidro and signed by a local judge.
"We have started to analyse the material that was taken" from Luque's home and office, the statement said.
"By virtue of the evidence that was collected, it was considered necessary to request searches at the home and office of doctor Leopoldo Luque."
Luque said in an interview with Argentinian newspaper Clarin: "I am sure that I did the best I could for Diego, the best I could.
"My family shouldn't have to suffer because of this. I can't read any of the stuff being written about me because I'm too sad as my friend has died.
"I was at his funeral and wake and people I didn't know were asking me why I wasn't with him - I couldn't believe it. I'm not responsible.
"I would like him to still be here. He wanted to live. I tried to take him places but he didn't want to go. He missed his parents a lot.
"His life changed and then he left us. It's very unfair but I would go back and do it all again.
"Police coming to my house ... I'm not to blame for anything, I'm proud of what I did. They arrived unexpectedly but I gave them everything they asked for."
The prosecutor's office did not provide any information on what prompted the investigation.
In later years, Maradona struggled with substance abuse issues.
"Diego was tired, tired of being 'Maradona'", Luque said.
Maradona's lawyer Matias Moria said on Thursday he would ask for a full investigation of the circumstances of the soccer legend's death, criticising what he said was a slow response by emergency service.
"The ambulance took more than half an hour to arrive, which was a criminal idiocy," Matias said in a Twitter post.