A drone that crashed in Zagreb on March 10 after flying for more than an hour and passing through the airspace of Romania and Hungary was carrying explosives, preliminary results of an investigation show.
The Soviet-era drone crashed in a park in southern Zagreb, waking up students in a nearby dormitory and damaging several parked cars but causing no injuries.
The State Attorney's Office and experts who presented the findings of the investigation at a news conference in Zagreb on April 13 said an explosion occurred when the drone hit the ground.
"Most likely, a high-energy but unconventional substance or mixture of substances of organic origin was used” to cause the explosion. The substances completely “chemically decomposed in the explosion,” making it impossible to identify what they were, said Ivana Bacic, the chief expert for fires and explosives at the Center for Forensic Investigations, Research and Expertise.
The crash caused anger and astonishment in Croatia because the drone spent almost an hour flying in the airspace of three NATO countries -- Romania, Hungary, and Croatia -- without a response.
NATO has not yet been notified about the preliminary findings of the investigation, officials said at the news conference.
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In the days after the crash Croatian government and military sources claimed the drone was carrying a bomb, while independent experts claimed it was a reconnaissance model used in aerial recording. NATO Secretary-General Jens Stoltenberg said five days after the crash that the drone wasn't armed.
The Ukrainian and Russian governments denied that the drone was fired from any areas they control and accused each other of launching it.
Jurica Ilic of the State Attorney's Office in Zagreb said that the investigation centered on why it fell from the sky and the investigation will continue to determine who launched the drone and from where.
Before crashing, the drone began a landing maneuver near the Croatian capital, but experts couldn't confirm whether Zagreb was its target. Experts suspect there was a malfunction in its automatic landing system.
Investigators determined after the crash that the drone was a TU-141 reconnaissance aircraft made in the 1980s in the former Soviet Union. But a red star on its wing had been painted over in blue and yellow, the colors of the Ukrainian flag, they said.
Ilic said investigators were reluctant to speculate on who sent the drone or where it came from.
"It is difficult for me to conclude who modified the aircraft and who modified the bomb and for what purpose. When we know who did it, we may get answers why," Ilic said.