To this Robespierre added two names, and then signed it and sent it back to the prison.

There was another list with the names of the prisoners to be executed on the following day, and this, Harry learned, was not sent in to the prison authorities until late in the evening, so that even they were ignorant until the last moment which of the prisoners were to be called for by the tumbrils next morning.

Thus he would know when Marie was to go through the mockery of a trial, and would also know when her name was put on the fatal list for the guillotine.

The first fact he might have been able to learn from his ally in the prison, but the second and most important he could not have obtained in any other way.
The work had been frequently interrupted by callers.

Members of the Committee of Public Safety, leaders of the Jacobin and Cordeliers Clubs, and others, dropped in and asked Robespierre's advice, or discussed measures to be taken; and after a day or two Harry found that it was very seldom, except when taking his meals, that Robespierre was alone while in the house; and as his sister was in and out of the room all day, the idea of compelling him by force to sign the order, as they had originally intended to do with Marat, was clearly impracticable.
Each day after his work was over, and this was generally completed by about one o'clock, Harry called to see how Victor was getting on.