CTK, Krumphanzl Michal, Associated Press
In this Oct. 11, 2013 file photo Palestinian ambassador to the Czech Republic Jamal Al Jamal is pictured in Prague, Czech Republic. Jamal Al Jamal, who was injured in an explosion in his residence in Prague-Suchdol, has died in a hospital on Wednesday, Jan. 1, 2014.

PRAGUE — Investigators were working to identify the explosive that killed the Palestinian ambassador, what caused the substance to explode and why it was being kept in an embassy safe, Czech authorities said Thursday.

Ambassador Jamal al-Jamal, 56 died Wednesday of massive injuries from the blast.

Police spokeswoman Andrea Zoulova said on Wednesday that it appeared that the door of the safe had been booby-trapped. It was unclear how al-Jamal tried to open it or what type of safe it was.

On Thursday, Zoulova told The Associated Press that nothing had been found to suggest the diplomat had been a victim of a crime. The country's counterintelligence service, BIS, also said it had no such evidence.

Zoulova declined to give any further details about the safe, citing an ongoing investigation.

Pavel Kolar, the head of Prague's Institute of Criminology, said Thursday that their investigation would take several days at least.

Palestinian Foreign Minister Riad Malki said no foul play was suspected.

Malki said the safe had been left untouched for more than 20 years. However, Palestinian Embassy spokesman Nabil El-Fahel told Czech radio it had been in regular use.

"(The safe) was used on a daily basis at the embassy and it was opened and closed almost every day," he said.

The embassy recently moved to a new complex, and the safe was in the ambassador's residence.

A team of Palestinian experts is expected to participate in the investigation.

Security analyst Andor Sandor said it is very unusual to protect any embassy documents by such excessive force.

During their search, police discovered one more safe at the embassy complex but no other explosives were found.