In her illness she always wanted her papier-mache statue of the "Ecce Homo" ("Behold the man", Jh 19,5) near her bed to keep constantly contemplating Him. She said that she had "received a vivid knowledge of the offenses, which are made to God by sinners. Thus she felt in herself such pain, which was expressed in that proposition: I would never have believed, that it was so much worth cognition, that one has of offenses made to God, greater than this I do not believe, can be given". Increased rheumatic pains, headaches, lung problems.
She spoke of the tests to be overcome by saying that she was constantly assisted by God. One evening, they bleeded her to alleviate her headache, but the following night she had "pains of gallstones". She faced also spiritual afflictions, the fear of not pleasing God in suffering.
It was proven by the thought of being unable to do good deeds. In her last infirmity she renewed her request to the Lord to experience the pains of his Passion. One day she confided to her confessor that Jesus had appeared to her crowned with thorns. During her last illness, from 6 to 9 pm every Friday, she lived the agony of Jesus on the cross again in herself.
In the harsh winter of 1743 her health conditions became worrisome. Pneumonia injured her body inexorably. She glanced at her statue "Ecce Homo". It was five o'clock in the morning on February 1st, 1743. Someone noticed that the last illness had lasted 33 days.
It was recalled that Sister Angela Catherine had complained about the excessive heat in her breast the day before. It was decided to ask for an autopsy. A singurar witness of that was the painter Giovanni Sorbi, who had just painted the portrait of Angela Catherine a few hours after her death. They found "little nerves" similar to nails in her heart. They were probably the cause of her pains, as they caused an irregular flow of blood.
When the news of her death spread, many people requested some objects of hers. Her room became a destination for devotees. It can be said that a certain reputation for holiness had surrounded Sister Angela Catherine while she was still alive, even though she was making fun of it.
People began to obtain some graces through her intercession. In fact, even today in the so-called "cave of the venerable" are kept a couple of crutches that a disabled friar left there for a miracle that he had received.
Someone reminded that St. Philip Neri visited the monastery in the 16th century and he said that one day, among those walls, a great saint would have lived.
A few months after her death the ordinary process of beatification was taught (years 1744-1748), followed by the canonical process. Interesting news was also noted in the Chronicles of the city of Fermo, whose author was her brother Alessandro. The process was stopped 1763, probably because of the events that shook the Papal State a few years later.