I think Interpol got involved, which if why the FBI is there.
FBI team heading to Beirut to join explosion investigation
The cause of the fire that ignited 2,750 tonnes of ammonium nitrate at the port of Lebanon’s capital remains unclear.www.aljazeera.com
Apparently there's still more questions, or at least things to confirm in regards to whether it was just an accident assisted by gross negligence or if some other factors might still be revealed.
Potentially it's going to be just like that movie starring Jamie Foxx, Jennifer Garner and Chris Cooper!