cheque for safety

I am so shocked ! A friend told me last week that a cheque she sent by mail went missing but it was shown as cleared in the bank statement. Anyhow, she reported this to the bank and just now, I received an email from her. The cheque was actually drawn by an individual person. Her bank has provided her with the name, identification (IC) and telephone number and a scanned copy of the cheque. How can such things happen lah ? We write the cheque, put it into the mail and assume that it will arrive its intended recipient safely. None of us expects our cheques to be hijacked right ? And how could the bank allow an altered cheque to slip through the system ?

WHO DUNNIT ????
Postman
Postal Staff
Individual public nuisance
Bank staff

Like I said to my friend...there must be a millionaire or billionaire in the making somewhere here in Malaysia !