Odd and destined to feed conspiracy theories because any oddness in a major catastrophe, especially one with political or cultural implications, ultimately feeds conspiracy theories.

The first fire alarm on Monday was set off at 6:20 p.m., and checks were carried out but no fire was found, Mr. Heitz said.

A second alarm went off at 6:43 p.m., he said, and fire was discovered in the wooden framework of the attic, ancient beams beneath the lead roof known as the “forest.”…

The cathedral’s rector, Msgr. Patrick Chauvet, said on Tuesday that fire monitors routinely inspected the cathedral. “Three times a day they go up, under the wooden roof, to make an assessment,” he told France Inter, a radio station.

He also said there was an on-site firefighter at the cathedral, although he did not say how often that person was there, where that person was normally stationed, or whether that person was present on Monday.

The sinister theory here, I guess, would be that some saboteur slipped up to the “attic” and set a fire, triggering the 6:20 alarm, but the fledgling fire burned itself out before firefighters arrived. So the saboteur waited for them to leave and then set a second fire, this one more successful. It would take mind-boggling brazenness to try to burn down the cathedral not once but twice, though, especially with firefighters having just been on the scene. And how you would go about doing this at a major tourist hub like the cathedral with no one spotting you is unfathomable to me. There was an arsonist in the “attic” for half an hour, with personnel sniffing around after the first alarm to try to detect a fire, and no one noticed anything? Seems unlikely.

Investigators say there’s no evidence of sabotage right now. Instead, they’re apparently looking at restoration work that was going on in the spire:

The focus of prosecutors is currently on contractors Le Bras Freres, whose owner Julien Le Bras last year boasted his firm’s goal was ‘to keep as many old items as possible and not to put the building at risk’ after they were awarded a €5.7m (£5m, $6.5m) contract as part of the cathedral’s restoration project.

Detectives investigating the catastrophic blaze are today interviewing specialist restorers who were carrying out works on the cathedral spire when the inferno broke out.

Another quarter-assed theory: Maybe work was going on which, unbeknownst to the contractors, was causing part of the roof to heat up. The heat may have triggered the first alarm, causing work to stop and the roof to cool down before it ignited. When no fire was found and work resumed, maybe it continued this time after the second alarm sounded and this time ignition was achieved. That is, after the first alarm revealed no fire, workers might have assumed there was a problem with the alarm system instead of recognizing that something was generating heat within the roof.

We’re in the dark and the investigation will be “long and complicated” due to the fact that the spot of ignition was apparently destroyed with the rest of the roof. Ed notes via email that although the Times piece quoted up top claims that “checks were carried out” after the first alarm sounded, it doesn’t specifically say that trained firefighters carried out those checks. Was it the on-site firefighter who did so? The “fire monitors” who carry out regular checks? Or was it someone less well-trained? (When an alarm sounds, notes the Times, the on-site firefighter can dispatch a “security agent” to check it out.) It may be that the fire was still in the smoldering stage when the first alarm sounded and whoever investigated simply didn’t recognize that anything was burning. It might have taken 23 more minutes before flame and smoke were visible, at which point it was too late.