Warning: mysqli_query() expects parameter 1 to be mysqli

I am having a minor problem with my code if any one can help.

I have a form where the user can add a new article however on submit this error is displayed:

Warning: mysqli_query() expects parameter 1 to be mysqli, object given in //public_html/admin/includes/addnews.php on line 12.

This is the code:

$auth = $_POST['auth'];
$tit = $_POST['tit'];
$stat = $_POST['stat'];
$shrt = $_POST['short'];
$art = $_POST['art'];


$conn = mysqli_connect("localhost","db","password","db") or die ("Could not connect to database");

$query = $conn->prepare ("INSERT INTO newsitem (author,title,shortdesc,article,newsdate,status) VALUES ('$auth','$tit','$shrt','$art',CURDATE(),'$stat')");
$result = mysqli_query($query,$conn);
	
if($result){
	
	echo "successful";
	echo "<BR>";
	echo "<a href='news.php'>Back to News </a>";
	
		}

else {
	echo "error could not upload article";
}

mysqli_close($conn);
?>

I have been looking at this for the last two hours with no hope, is there anyone who can point me in the right direction please?