This would be a duplicate, but I really need a good solution. I have tried to research but failed to find anything.
Not to complicate, I know it is easy if I just used a `GET` method, but I needed to use `DELETE` method. Using `DELETE` would be easy for the api that I'm sending the request to directly call its `Delete` method. 

I know I should not set the `Body` but, how I'am able to send the `id` to the api?

**Code Snippet:**

    HttpRequest req = new HttpRequest(); 
    HttpResponse res = new HttpResponse(); 
    Http http = new Http(); 

    req.setEndpoint('testsite.com/api/User'); 
    req.setMethod('DELETE'); 
    req.setBody('29'); 
    req.setHeader('Content-Type', 'application/json'); 

    try { 
      res = http.send(req); 
    } 
    catch(System.CalloutException e) { 
      System.debug('Callout error:' + e); 
    } 

    System.debug(res.getBody());