The idea, however unlikely, that a survivor could be found gave hope to people who followed the live images on television.
Many Lebanese families plan to leave the country in search of safety and security following August 4 port explosion.
Caretaker justice minister says mistrust in judiciary is warranted but dismisses calls for international investigation.
Legal action could be first of many moves as anger builds over disaster, with protests planned on Saturday
A warehouse storing thousands of tons of unsecured highly explosive material has emerged as a possible source of the massive blast that ripped through the Lebanese capital on Tuesday, killing at least 100 people, injuring 4,000 and sending a shock wave across the city that damaged buildings and blew out windows up to 10 kilometers (6 miles) away.
A massive explosion ripped through central Beirut on Tuesday, injuring hundreds of people and blowing out windows in buildings across the city.