But my notary, calling to mind his servant’s dream, proposed to his companion that they should go to the cemetery which their host had talked about without him. So, having found and hired a guide, they went in the first place to the basilica of the blessed Tiburtius in the Via Labicana, about three thousand paces from the town, and cautiously and carefully inspected the tomb of that martyr, in order to discover whether it could be opened without any one being the wiser. Then they descended into the adjoining crypt, in which the bodies of the blessed martyrs of Christ, Marcellinus and Petrus, were buried; and, having made out the nature of their tomb, they went away thinking their host would not know what they had been about. But things fell out differently from what they had imagined. (Cap. i. 7.)
In fact, Deacon Deusdona, who doubtless kept an eye on his guests, knew all about their manoeuvres and made haste to offer his services, in order that, “with the help of God” (si Deus votis eorum favere dignaretur), they should all work together. The deacon was evidently alarmed less they should succeed without his help.
So, by way of preparation for the contemplated vol avec affraction they fasted three days; and then, at night, without being seen, they betook themselves to the basilica of St. Tiburtius, and tried to break open the altar erected over his remains. But the marble proving too solid, they descended to the crypt, and, “having evoked our Lord Jesus Christ and adored the holy martyrs,” they proceeded to prise off the stone which covered the tomb, and thereby exposed the body of the most sacred martyr, Marcellinus, “whose head rested on a marble tablet on which his name was inscribed.” The body was taken up with the greatest veneration, wrapped in a rich covering, and given over to the keeping of the deacon and his brother, Lunison, while the stone was replaced with such care that no sign of the theft remained.