The matter now appearing to be grave, additional scientific assurance was sought. Three of the most distinguished chemists in Paris were called into service for a further analysis. They were MM. Devergie, Pelouze, and Flandin. Their report ran in part:
The portion of the liver on which we have experimented proved to contain a notable quantity of arsenic, amounting to more than five milligrammes; the portions of the intestines and tissue examined also contained appreciable traces which, though in smaller proportion than contained by the liver, accord with the known features of arsenical poisoning. There is no appearance of the toxic element in the earth taken from the grave or in the material of the coffin.
As soon as Mme Lacoste was apprised of the findings of the autopsy she got into her carriage and was driven to Auch, where she visited a friend of her late husband and of herself. To him she announced her intention of surrendering herself to the Procureur du Roi. The friend strongly advised her against doing any such thing, advice which Mme Lacoste accepted with reluctance.
On the 5th of January a summons to appear was issued for Mme Lacoste. She was seen that day in Auch, walking the streets on the arm of a friend. She even went to the post-office, but the police agents failed to find her. She stopped the night in the town. Next day she was at Riguepeu. She was getting out of her carriage when a servant pointed out gendarmes coming up the hill with the Mayor. When those officials arrived Euphemie was well away. Search was made through the house and outbuildings, but without result. "Don't bother yourself looking any further, Monsieur le Maire," said one of the servants. "The mistress isn't far away, but she's in a place where I could hide a couple of oxen without you finding them."
From then on Mme Lacoste was hunted for everywhere. The roads to Tarbes, Toulouse, and Vic-Fezensac were patrolled by brigades of gendarmes day and night, but there was no sign of the fugitive. It was rumoured that she had got away to Spain, that she was cached in a barrel at Riguepeu, that she was in the fields disguised as a shepherd, that she had taken the veil.
In the meantime the process against her went forward. Evidence was to hand which seemed to inculpate with Mme Lacoste a poor and old schoolmaster of Riguepeu named Joseph Meilhan. The latter, arrested, stoutly denied not only his own part in the supposed crime, but also the guilt of Mme Lacoste. "Why doesn't she come forward?" he asked. "She knows perfectly well she has nothing to fear—no more than I have."
From the 'information' laid by the court of first instance at Auch a warrant was issued for the appearance of Mme Lacoste and Meilhan before the Assize of Gers. Mme Lacoste was apparently well instructed by her friends. She did not come into the open until the last possible moment. She gave herself up at the Auch prison on the 4th of July.
Her health seemed to have suffered little from the vicissitudes of her flight. It was noticed that her hair was short, a fact which seemed to point to her having disguised herself. But, it is said, she exhibited a serenity of mind which consorted ill with the idea of guilt. She faced an interrogation lasting three hours without faltering.
On the 10th of July she appeared before the Gers Assize Court, held at Auch. The President was M. Donnoderie. Counsel for the prosecution, as it were, was the Procureur du Roi, M. Cassagnol. Mme Lacoste was defended by Maitre Alem-Rousseau, leader of the bar of Auch.
The case aroused the liveliest interest, people flocking to the town from as far away as Paris itself—so much so that at 6.30 in the morning the one-time palace of the Archbishops of Auch, in the hall of which the court was held, was packed.