In Brazil, criminal gangs frequently phone victims with fake abduction claims about their loved ones and trick them into handing over cash. As the BBC's Gary Duffy reports from Sao Paulo, being on the receiving end can be a frightening experience.
Gary Duffy is just one of thousands targeted by the scam
When the call came it was a sudden intrusion on a quiet Sunday afternoon.
At the other end of the line appeared to be a young man in a great deal of distress, crying desperately.
"Oh My God," he said repeatedly, "I've just been robbed... they have taken me." And then he called out: "My mother, my mother."
Suddenly an older man came on the line and almost casually explained they had meant to kidnap the son of a businessman but had taken this young man instead. He demanded to speak to the mother in the household.
It seemed a good moment to put the phone down.
Bogus phone calls
It was clear that someone was trying to make us a victim of the kind of virtual kidnapping that is one of the more sinister aspects of crime across Latin America.
The police are in a never-ending war with kidnapping gangs
Anyone with a phone can be singled out. The virtual kidnappers, if you could call them that, try to panic the person they call - often a mother or a father - into going to a bank and paying out a ransom before there is time to actually check if their relative is missing.
In most cases no-one has actually been abducted.
Time and fear and the aggressive manner of the caller are the key elements of this type of crime.
The virtual kidnappers have sometimes monitored a family to get details of names and movements, but on other occasions it seems to be less sophisticated.
A mobile phone is stolen and the criminals simply ring the pre-programmed numbers for mum or dad or home.
The voice of the sobbing victim is often actually just a recording, while the caller is working from a script. In a state of panic, the victims often give away details that allow the caller to pretend they know more than they actually do.
In 2006, in just five Brazilian cities, nearly 10,000 people reported that they had been victims of this type of crime, and this is just the cases that have been registered.
We recently were passing a bank in Avenida Paulista - in the heart of Sao Paulo - when we heard a woman shouting in a loud, almost hysterical voice on a mobile phone: "I'm at the bank, I'm at the bank."
People nearby said she was trying to deal with virtual kidnappers, and they contacted the police.
In one case, a 67-year-old woman who had gone to a bank to get money following this kind of threatening call had a heart attack and later died.
I have to say until a call comes through on your own phone you tend to think you would not be the sort of person to be intimidated by this kind of crime.
But to suddenly get a call from a crying man on a Sunday afternoon, claiming he has been kidnapped, can be an alarming experience.
As I do not have any immediate family in Brazil it was easy to set any concerns to one side, and immediately identify the call as bogus.
But it is also a bit easier now to imagine how in the shock of the moment, logical thinking could be set to one side by a scared mother or father.
Some of these calls are actually made by criminals who have access to mobile phones inside prison. Associates on the outside are then used to collect money from where the terrified victims have left it, often without contacting the police or seeking help.
In many other cases the victims are made to pay for credit to be added to the mobile phones held by the prisoners inside jail.
Undoubtedly this kind of call has more impact because the high levels of crime in Brazilian society make the threat seem real.
In Brazil when someone is actually taken hostage this is sometimes known as a "lightning kidnap".
The person is held for a few hours, and either they are made to go to a bank to get money, or someone from their family is called to do this instead.
One in five
Even though figures show this type of crime is declining significantly, it seems the fear of abduction has not diminished.
Police recordings show that even when the virtual kidnappers get basic facts wrong, such as saying they have taken a boy hostage when the person only has daughters, victims have still been tricked into paying out money.
Research done by the department of state security in Sao Paulo showed 20% of victims believed in the story given by the criminals making the call and handed over a ransom.
All this has a tendency to make you a little paranoid about some of the telephone calls you get in Brazil.
For some reason I have never quite worked out, you seem to get a higher than average number of calls here made by people who have got the wrong number.
There then follows an awkward exchange as you try to politely set the caller straight while at the same time avoiding giving away any details about you or your personal life.
It seems a sensible precaution.
But it is also a sad reflection on our times that a modern means of communication that so often brings families together could be used instead as a way of spreading fear.
From Our Own Correspondent was broadcast on Saturday 25 August, 2007 at 1130 BST on BBC Radio 4. Please check the programme schedules for World Service transmission times.