PHP code function not working properly - php

Question

I have a PHP file where I use the following PHP code to access my DB to retrieve some data to create a geojson. It does return a geojson but all html etc is exluded when i call this function.
<?php
require_once("db.php");
$geo = connectToDB::getGeoJSON();
?>
This is the function im calling from another a db.php file.
public static function getGeoJSON() {
$db_connection = new mysqli(mysqlServer, mysqlUser, mysqlPass, mysqlDB);
$statement = $db_connection->prepare("Select poiId, lat,lng,description from poi");
$statement->bind_result( $id, $lat, $lng, $description);
$statement->execute();
$feature = array();
$geojson = array(
'type' => 'FeatureCollection',
'features' => $feature
);
while ($statement->fetch()) {
$feature = array(
'type' => 'Feature',
'geometry' => array(
'type' => 'Point',
'coordinates' => array($lng, $lat)
),
'properties' => array(
'description' => $description
//Other fields here, end without a comma
)
);
array_push($geojson, $feature);
}
$statement->close();
$db_connection->close();
//Return routing result
header("Content-Type:application/json",true);
return $geojson;
}
Can anyone see whats wrong with the code? It does return the correct output but then the rest of the page wont show. Other functions I call is working normally so its the geojson function something is wrong with.