The step-granddaughter of award-winning actor Morgan Freeman has been killed in a frenzied knife attack near her home in Manhattan.

The perpetrator, identified by the New York Post as an ex-boyfriend, screamed "Get out, devils! I cast you out, devils! In the name of Jesus Christ, I cast you out!" as he stabbed E'Dena Hines, 33, whose grandmother was Freeman's first wife.

While no further details have been released, the immediate assumption is that Lamar Davenport – who is known to have abused alcohol and drugs – is mentally ill.

Freeman said in a statement: "'I want to acknowledge the tremendous outpouring of love and support my family has received regarding the tragic and senseless passing of my granddaughter E'Dena Hines."

However, the tragedy highlights uncomfortable questions for Christians. It is not the only case in which someone has been attacked in an attempt to "exorcise" them. In the UK, cases like that of Victoria Climbié, murdered by her great-aunt and her boyfriend at the age of eight, and 15-year-old Kristy Bamu, drowned in a bath during a days-long exorcism, have led to soul-searching and criticism of the authorities.

In these cases, what lay behind the assaults was the belief, prevalent in some African communities – and accepted in some Pentecostal-type churches in the UK – in "kindoki", witchcraft or demon-possession. We don't know what the background to the Manhattan attack was. It may be that the perpetrator had been influenced by Hollywood more than by theology or church teaching – films like The Exorcist and Rosemary's Baby have taught generations of film buffs a particular view of possession and their narrative has pervaded a whole culture.

On the other hand, there are sections of the Church that enthusiastically proclaim the reality of demons and demon-possession. Their point of departure is the New Testament, but they sometimes depart quite a long way. They may not go as far as physical violence, but the line can be crossed: in the Lakeland Revival of 2008, for instance, evangelist Todd Bentley would exorcise spirits from his audience by punching and kicking them.

These practices are flatly rejected by serious practitioners of what is called "deliverance ministry". Bishop Dominic Walker, co-chair of the Christian Deliverance Study Group and author of The Ministry of Deliverance, told Christian Today: "There is no justification whatever for violence or physical assault when carrying out an exorcism.

"Exorcisms in the Bible are carried out by a verbal command without any physical action. Most pastoral guidelines stress the need to avoid any harm to the sufferer who might become disturbed and violent during an exorcism, so the person may be seated in a padded comfortable chair and others present might provide gentle restraint but those carrying out ministry should never use violence or physical assault."

Underlying the whole issue, though, is the question of what is actually meant by "possession" and of the existene and nature of evil spirits. The New Testament clearly refers to Jesus "casting out" demons, for example in the story of the man afflicted by a "legion" of evil spirits in Matthew 8. However, the nature of these spirits is never spelt out, and our reading of such passages is conditioned by centuries of Christian theology and myth-making.

Walker says that "there is biblical and historical support to say that a person may be possessed by an evil spirit", though he adds that in Anglican churches there are strict rules regarding diagnosis and ministry, so an exorcism may only be carried out by a priest authorised by the bishop and then only after medical advice – usually psychiatric – and in a safe context.

However, he says: "The theological and psychological question is what is meant by 'possession by an evil spirit'. Some believe that such a 'possession state' is brought about by an external spirit while others would regard the spirit to be a disturbed part of the person's unconscious mind that is manifesting itself as possession."

The whole area of deliverance ministry is fraught with peril for the unwary. Approached uncritically and without deep reflection and preparation, it can lead to appalling abuse and real tragedies.

Perhaps more commonly, though, it can simply be deceptive. Blaming our faults and sins on an external agent is very tempting. If we are taught that our lust, greed, laziness or bad temper is the result of demonic oppression, we may be less inclined to take responsibility for it. If a ministry is suffering or a church is failing, it's easier to blame attacks by the Devil than it is to take a hard look at what we might be doing wrong.

And an uncritical approach deliverance ministry is also responsible for spiritual abuse. It's possible to project our fears, insecurities and prejudices on to another people, so that we begin to see them as the focus of all that's wrong in our own lives. With the right kind of wrong theology they become the incarnation of evil, and hostility towards them becomes sanctified.

In the Church of England, Walker explains, "while spiritual oppression is common, true possession is regarded as being very rare". Each case is carefully investigated and exorcisms are only carried out with the proper safeguards.

It would be very foolish to deny the reality of evil, in view of the biblical witness and the experience of the Church through the ages. But it is foolish, too, to enter this arena without thought, prayer and study – and without discarding everything Hollywood has taught us.

Follow @RevMarkWoods on Twitter.