Paraic O’Brien:

He went on to say that France would invite architects from around the world to submit designs for a new spire to replace the one that fell in Tuesday's fire.

The focus of the investigation now moves to here, the headquarters of the Parisian judicial police. There are 50 investigators inside this building all asking the question, why did the fire start? As part of that, they're interviewing contractors who were working on the renovation at the cathedral. And of particular interest will be the company walking at the base of the famous spire, where the fire was most intense.

The company is run by Julien Le Bras. His company won the $5 million contract to repair the spire. The company's corporate video shows him talking to his staff about the project at the time.

Yesterday, outside the cathedral, he said he was cooperating with investigators and that none of his employees were on site when the fire started.