By Alix Kroeger
BBC News, Kabul
Early investigations into Tuesday's bombing in the Afghan province of Baghlan indicate that the attacker used ball bearings to maximise casualties.
The ball bearings were mixed with explosives, the interior ministry says.
Efforts to establish an accurate casualty toll will get underway later on Friday.
The provincial governor says the death toll now stands at 52, with 106 people injured. The Taleban have denied that they were responsible.
This is not the first time an Afghan suicide bomber has used ball-bearings to increase the force of the blast, but it is certainly the deadliest.
Investigators at the scene of Tuesday's bombing found ball bearings scattered around.
The interior ministry estimates around 1,000 may have been used, one of the reasons the death toll was so high.
Credible estimates range from 52 to 75. Other figures go even higher.
Later on Friday, officials will go house to house in Baghlan, asking if any members of the family were killed in the blast.
This is necessary because some families took away the bodies of their relatives before they could be added to the casualty figures.
The police chief and the provincial governor of Baghlan have come in for criticism because they were out of town when the bomb went off.
They have defended their actions.
The police chief said he was at a conference, while the governor was meeting one of Afghanistan's vice-presidents in the city of Mazar-e-Sharif.
But in the absence of any evidence as to who carried out the attack, that has not been enough to stop the rumours and speculation swirling around the country.