Police in Argentina seized information tied to Maradona's treatment and medical history from his doctor, Leopoldo Luque, after questions over the former soccer player's death were raised.
Thousands of fans lined up from the early hours on Thursday to file past Maradona's wooden casket in the presidential palace. Argentina's beloved soccer star died on Wednesday.
The former president crossed the border from Argentina and was welcomed by a large group of supporters, just a day after his former economy minister, Luis Arce, was sworn in as president.