Swift - Crash when try to get JSON values for second time - json

Question

I am trying to get an array of values from a JSON file using Swift. I found the way to get the values printed when a button is pressed using a IBAction method.
The Function is printing the array fine the first time the button is pressed however, if I press the button again the app crashes giving the error:
fatal error: unexpectedly found nil while unwrapping an Optional value
(lldb)
The array that I get the first time from printing jsonResult looks Like:
1: {
Age = 30;
Email = "info#example.com";
Location = Rome;
MyText = "Design Agency";
Name = Admin;
Password = 123456;
REF = 002;
"Reg_Date" = "2015-07-28";
Sex = Male;
Surname = "Mobile App"; }
2: {
Age = 30;
Email = "example#gmail.com";
Location = London;
MyText = "aaaaaaaaa";
Name = Andrew;
Password = 123456;
REF = 001;
"Reg_Date" = "2015-07-28";
Sex = Male;
Surname = Nos; }
It seems that the second time I call the function, it cannot read the file anymore.
Whats wrong with my code? Do I need to close the connection?
#IBAction func login_button(sender: AnyObject) {
searchFunction()
}
func searchFunction() {
var tempUrlValue = loginJsonResults.stringForKey("loginJsonResults")
let urlPath: String = "https://example.com/iOS/users_result.json"
var url: NSURL = NSURL(string: urlPath)!
var request: NSURLRequest = NSURLRequest(URL: url)
var connection: NSURLConnection = NSURLConnection(request: request, delegate: self, startImmediately: false)!
connection.start()
}
func connection(connection: NSURLConnection!, didReceiveData data: NSData!){
self.data.appendData(data)
}
func connectionDidFinishLoading(connection: NSURLConnection!) {
var err: NSError
var jsonResult: NSMutableArray = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: nil) as! NSMutableArray
//Call jsonResult Values
var temporaryString: AnyObject = jsonResult[1]
for (index, jsonResult) in enumerate(jsonResult){
println("\(index + 1): \(jsonResult)")
countUsers++
}
println(countUsers)
}