According to the sources, Thousands mourned the Ethiopian plane crash victims on Sunday, accompanying 17 empty caskets draped in the national flag through the streets of the capital as some victims' relatives fainted and fell to the ground.
Family members confirmed they were given a 1-kilogram sack of scorched earth taken from the crash site.
Many relatives already have gathered at the rural, dusty crash site outside Ethiopia's capital.
The victims Ethiopian Airlines Flight 302 came from 35 countries and included many humanitarian workers headed to Nairobi.
Experts from the US National Transportation Safety Board and the plane's manufacturer Boeing are among those involved in the investigation.
The US Federal Aviation Administration has said satellite-based tracking data shows that the movements of Ethiopian Airlines Flight 302 were similar to those of Lion Air Flight 610, which crashed off Indonesia in October, killing 189 people.
Both involved Boeing 737 Max 8 planes.
The Ethiopian disaster and a crash last year in Indonesia were both of the Boeing 737 Max 8 planes.
The United States and many other countries have grounded the Max 8s.