A judicial police official said the investigators made an initial assessment of the cathedral Wednesday April 17th but do not have a green light to search Notre Dame's charred interior because of ongoing safety hazards in the structure.
The cathedral's fragile walls were being shored up with wooden planks, said the official, who spoke on condition of anonymity because he was not authorized to speak about an ongoing investigation.
Investigators so far believe the fire was accidental, and are questioning both cathedral staff and workers who were carrying out renovations. Some 40 people had been questioned by Thursday April 18th, according to the Paris prosecutor's office.
The police official would not comment on an unsourced report in Le Parisian newspaper that investigators are looking at whether the fire could have been linked to a computer glitch or the temporary elevators used in the renovation work, among other things. The prosecutor's office said only that "all leads must be explored."
President Emmanuel Macron held a ceremony Thursday April 18th at the Elysee Palace to thank the hundreds of firefighters who fought the fast-moving fire at Notre Dame, whose actions saved the building from destruction and rescued many sacred religious and artistic artefacts.
The cathedral’s roof and spire has been destroyed, but Notre Dame’s famous bell towers, rose windows and historic organ have all been saved.