It`s Me Fraud

I`d like to discuss about 「It`s me fraud」.Do you know what it is??I`m talking about the case of my grandmother to explain it.
One day,my grandmother got a phone call from someone.But he did`t say his name.Just he said 「It`s me...It`s me」.My grandmother thought he was her son.And,she asked him 「Are you Ken??」and someone answered「yes,I`m Ken」.Actually,he was not his son.He was a co-man.And then,he was explaining about his trouble.「I had a car accident.so I need some money.Can you send me some money??」and he gave his bank account number to my grandmother.She was so upset,and she went to a bank without talking about it with anyone.But recently this fraud often happened,so police or banker watched old person to prevent from deceiving.At the time,the banker asked her「Is he your real son??,you should check it again」.She trusted it,but she tried to call his son.Finally,she noticed it was the fraud.
Stated quite simply,this is a fraud in which a co-man calls an elderly person,pretends to be a son or grandson,and ask for money.Now the fraud like this is going to disappear because of being well-known.However,new type of fraud is appearing.So,we always must be careful.