How to convert NSString to JSON format in ios5?

I have some String values, such as this format,

[INFO]  [Tue Aug 21 14:54:22 2012]  [ViewController]  [26]  [Hello]  [;]

I want to convert these strings to JSON using NSJSONSerialization.

I use the following code to convert strings,

 for (i = 0; i < [logArray count]; i++) 
{
    individualLogInfoArray = [[logArray objectAtIndex:i] componentsSeparatedByString:kDelimitterSpace];
    [dictionaryArray addObject:individualLogInfoArray];

}

finalLogDictionary = [NSMutableDictionary dictionaryWithObjectsAndKeys:dictionaryArray,@"Log", nil];
    NSError *error;
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:finalLogDictionary 
                                                   options:NSJSONWritingPrettyPrinted
                                                     error:&error];

NSString *jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
NSLog(@"JsonString = %@",jsonString);

Then I get the output as follows:

JsonString = {
  "Log" : [
    "[INFO]  [Tue Aug 21 14:54:22 2012]  [ViewController]  [26]  [Hello]  [;]",
    "[DEBUG]  [Tue Aug 21 14:54:22 2012]  [ViewController]  [27]  [hi]  [;]",
    "[INFO]  [Tue Aug 21 14:54:22 2012]  [ViewController]  [28]  [Its  there]  [;]",
    "[PROD]  [Tue Aug 21 14:54:22 2012]  [ViewController]  [29]  [Welcome]  [;]"
  ]
}

but I want it to be so

{
"log": "[INFO]  [Tue Aug 21 14:54:22 2012]  [ViewController]  [26]  [Hello],[INFO]  [Tue Aug 21 14:54:22 2012]  [ViewController]  [26]  [Hello],[INFO]  [Tue Aug 21 14:54:22 2012]  [ViewController]  [26]  [Hello]"

}

I do not know how to create a JSON string in the above format, please suggest a solution.