A search of properties belonging to Maradona's personal doctor was ordered by officials on Sunday, a local prosecutor’s office said.
Government officials say they are "keeping track" of the incident.
Most of the victims were children, who were working in a car wash close to the suicide bombing site.
Women in Saudi Arabia took to the roads at midnight on Sunday, ushering in the end of the world’s last ban on female drivers, long seen as an emblem of women’s repression in the deeply conservative Muslim kingdom.
The attack was launched by an unidentified assailant moments after 41-year-old prime minister, a former soldier who took office in April, finished his speech to tens of thousands of people gathered in Meskel Square in the center of Addis Ababa.
Roads in the area were closed and a large police presence was at the scene, with heavily armed tactical officers arriving as part of the large emergency response.
Eight journalists lost their lives covering the blasts after a suicide bomber attacked them.
The company acknowledged last month that a "privacy mishap" had affected 50-million users.
South Africans took offence at how Winnie Madikizela-Mandela's death was reported in the international press.
Officials are investigating the cause of the blaze.