"That is a possessed woman there," says Fr Vincenzo Taraborelli as he points up to an 18th Century fresco in his Roman church. "They're holding her with her mouth open. She has little devils coming out of her body. She's being freed."
It is a scene the 79-year-old priest says he knows well. For the past 27 years, Fr Taraborelli has performed exorcisms - the Catholic rite of expelling evil spirits.
He stumbled into the job when a fellow priest needed help.
"I didn't know what it was, I hadn't studied it," the father says. "He told me what to do. I was totally ignorant."
He has since become one of Rome's busiest exorcists, and the Catholic Church is struggling to find younger successors.
Working three days a week from a windowless room at the back of his church near the Vatican, he often sees up to 30 people every day.
"Before doing exorcisms I urge people to see a psychologist or a psychiatrist, and I ask them to bring me their prognosis. I'm in touch with many psychologists who send their patients here."
On one side of the room, a cabinet is filled with hundreds of small statues of angels. In a drawer, he keeps a supply of sweets to hand out to his visitors. On the wall is an official document showing his qualification as an exorcist.
Fr Taraborelli's desk is crowded with papers, photos, and prayer books. He sits in a simple chair; those who come to see him sit opposite him.
"First of all, I get the room ready," he says. "Then if the person is not doing well, I try to calm them down reassure them. I invite them to join me in prayer. But many of them when they come here are already disturbed."
He looks through his copy of the Catholic Church's exorcism rites. He's had to tape it back together to stop it from falling apart. Amidst the pile of papers on his desk, he finds the cross he uses to expel evil spirits.
His most notable case involved a married woman he treated for 13 years.
"Another man, who was a Satanist, wanted her," he remembers. "She refused. So this man told her: 'You'll pay for this.' He cast so-called spells to attract her to him, twice a week.
"Then they came to me, in this room. I started to pray, and she went into a trance. She would blurt out insults, blasphemies. I quickly understood she was possessed.
"As the rite continued, she started feeling worse and worse. So when I told the devil: 'In the name of Jesus, I order you to go away', she started to vomit little metal pins, five at a time.
"Aside from pins she would also vomit hair braids, little stones, pieces of wood. It sounds like something from another world right? Instead, it's something from this world."
Exorcism and the Catholic Church
Within the Catholic Church, the concept of possession by demons is an accepted belief.
It is sometimes used to explain murderous behaviour, as in the recent murder of 85-year-old French priest Fr Jacques Hamel in his church in the French city of Rouen in July.
When two Islamist militants acting in the name of jihadist group Islamic State (IS) burst into the church and stabbed Fr Hamel, he tried to fend them off, crying out "Be gone, Satan!" - an apparent attempt at exorcism.
In support of the priest's actions, Pope Francis accelerated the process of Fr Hamel's candidacy for sainthood.
But outside the Catholic Church, many dispute the entire basis of demonic possession and exorcism.
Non-believers argue that so-called possession by evil spirits is simply a medieval superstition or myth. Those who claim to be possessed by evil spirits are people suffering from easily explicable psychological or psychiatric problems, they say.
Fr Taraborelli rejects the scepticism.
"Well, someone who isn't a believer doesn't believe in the devil either," he says, "But someone who believes knows that the devil exists, you can read it in the gospel. Then you only need to see how the world is nowadays. It has never been this bad. These violence acts are not human. So terrible, like IS."
Fr Taraborelli shows no sign of wanting to give up his work and his mobile phone rings constantly.
But younger priests are not particularly attracted by the prospect of spending hours in windowless rooms, reading exorcism rites to disturbed believers.
"I told the bishop that I can't find anyone willing to do this. Many of them are scared. Even priests can be scared. It's a difficult life."