This threat cost Caterina her life.  About midnight, while a thunder-storm was raging, Virginia, accompanied by her usual associates, Ottavia, Benedetta, Silvia, and Candida, entered the room where the girl was confined.  They were followed by Osio, holding in his hand a heavy instrument of wood and iron, called piede di bicocca, which he had snatched up in the convent outhouse.  He found Caterina lying face downward on the bed, and smashed her skull with a single blow.  The body was conveyed by him and the nuns into the fowl-house of the sisters, whence he removed it on the following night by the aid of Benedetta into his own dwelling.  From evidence which afterwards transpired, Osio decapitated the corpse, concealed the body in a sort of cellar, and flung the head into an empty well at Velate.

The disappearance of Caterina just before the visitation of Monsignor Barca, roused suspicion; and, though a murder was not immediately apprehended, the guilty associates felt that the cord of fate was being drawn around them.  In the autumn of 1607 the tempest broke upon their heads.  Virginia was removed from Monza to the convent called Del Bocchetto at Milan; and on November 27 the depositions of the abbess, prioress, and other members of S. Margherita were taken regarding Osio’s intrigues, the assassination of Soncini, and the disappearance of Caterina.

Among the nuns who had abetted Osio, the two most criminally implicated were Ottavia and Benedetta.  Their evidence, if closely scrutinized, must reveal each secret of the past.  It was much to Osio’s interest, therefore, that they should not fall into the hands of justice; nor had he any difficulty in persuading them to rely on his assistance for contriving their escape to some convent in the Bergamasque territory.  We may wonder, by the way, what sort of discipline was then maintained in nunneries, if two so guilty sisters counted upon safe entrance into an asylum, provided only they could leave the diocese of Milan for another.[190] On the night of Thursday, November 30, 1607, Osio came to the wall of the convent garden, and began to break a hole in it, through which Ottavia and Benedetta crept.  The three then prowled along the city wall of Monza, till they found a breach wide enough for exit.  Afterwards they took a path beside the river Lambro, and stopped for awhile at the church of the Madonna delle Grazie.  Here the sisters prayed for assistance from our Lady in their journey, and recited the Salve Regina seven times.  Then they resumed their walk along the Lambro, and at a certain point Ottavia fell into the river.  In her dying depositions she accused Osio of having pushed her in; and there seems little doubt that he did so; for while she was struggling in the water, he disengaged his harquebuss from his mantle and struck her several blows upon the head and hands.

[Footnote 190:  In ecclesiastical affairs the diocese of Milan exercised jurisdiction over that of Bergamo, although Bergamo was subject in civil affairs to Venice.  This makes the matter more puzzling.]