I am a little confused; your opening states that you sent him the letter on 24th May 2013, but you end by saying that you are planning to send the letter by registered post.
If you have already sent the letter on 24th May then you should write to him stating that as he has failed to return a signed copy then it is deemed to have been accepted.
Send him a second letter (with a copy of the original), terminating his employment.
If you have not yet sent the letter, then add the following:
"Should you fail to respond to this letter your employment will be terminated".
I hope the above helps.
15th June 2013 From United Kingdom, Barrow
I need your suggestion and advice on the above mention post. I have sent him the letter by registered post on 17th June and now management has decided to terminate his service. We are planning to give one month notice to him as mentioned in employment contract.
I am waiting for your post.
20th June 2013 From India, Bhubaneswar