Update to this story.

PRAGUE (Reuters) – Czech investigators found unregistered weapons at the Palestinian diplomatic mission in Prague, police said on Thursday, a day after the ambassador was killed in a mysterious explosion after opening a safe.

“We have gathered many pieces of evidence, we secured weapons that will be subject to expert evaluation,” Prague police chief Martin Vondrasek said on Czech Radio.

“We can say the weapons have not gone through a registration process in the Czech Republic,” he said, without revealing the quantity and type.

Police reiterated their belief that the blast on New Year’s Day may have been caused by mishandling an explosive that could have been securing the safe. They have said they are not treating it as an attack or a terrorist incident.

Jamal suffered lethal injuries to his head, chest and abdomen. He had been in Prague only since October.

Embassy spokesman Nabil el-Fahel said the safe was being used on a daily basis to store cash for the mission.

The mission is in the process of moving into a new embassy and residence, which share the same compound. Jamal was killed at the new residence.