diff --git a/models/Authentication.php b/models/Authentication.php
index afcc55d..8793282 100644
--- a/models/Authentication.php
+++ b/models/Authentication.php
@@ -12,22 +12,6 @@
  */
 class Authentication
 {
-	/**
-	 * Checks whether a user still exists in the database.
-	 */
-	public static function checkExists($id_user)
-	{
-		$res = Registry::get('db')->queryValue('
-			SELECT id_user
-			FROM users
-			WHERE id_user = {int:id}',
-			[
-				'id' => $id_user,
-			]);
-
-		return $res !== null;
-	}
-
 	/**
 	 * Checks a password for a given username against the database.
 	 */
@@ -78,8 +62,18 @@ class Authentication
 	 */
 	public static function isLoggedIn()
 	{
-		// A user is logged in if a user id exists in the session and this id is (still) in the database.
-		return isset($_SESSION['user_id']) && self::checkExists($_SESSION['user_id']);
+		if (!isset($_SESSION['user_id']))
+			return false;
+
+		try
+		{
+			$exists = Member::fromId($_SESSION['user_id']);
+			return true;
+		}
+		catch (NotFoundException $e)
+		{
+			return false;
+		}
 	}
 
 	/**