How to remove information from info window

I am working with a Google Map API and I have imported a kml layer into my code.My problem is that I don't know how to remove the 'Unknown Point Feature' information from the info window. Any suggestions? here is a screenshot of what I am talking about:

This is my code for importing the kml file:

var AI_url = 'http://ift.tt/1G9eXUn'            
var AI_options = {
    preserveViewport: true,
    map: map
};
var AI_layer = new google.maps.KmlLayer(AI_url, AI_options);