aFile.remove() not working as expected

Trying to find out why the code below is not deleting all files from the target folder.

After some test it appears that only graphic files (jpg, png, gif) are being removed, skipping pdf, txt, eps, doc, docx, etc.

Have you seen this happening before? Thanks,

#target framemaker

var aGraphicFiles = [];

//Check for target folder existance, if not, create.
var myTargetFolder = new File("C:\\Basket2\\XML Tests\\BookFolder\\Resources\\DeleteMe");
if (!checkFolderExists(myTargetFolder)){ //target folder does not exist
    myTargetFolder = new Folder("C:\\Basket2\\XML Tests\\BookFolder\\Resources\\DeleteMe");
    myTargetFolder.create();
}

//Check if folder DeleteMe is empty
myTargetFolder = new Folder("C:\\Basket2\\XML Tests\\BookFolder\\Resources\\DeleteMe");
aGraphicFiles = myTargetFolder.getFiles();
if (aGraphicFiles.length != 0){
    for (i=0; i<aGraphicFiles.length; i++){ //scan array
        var sourceChild = aGraphicFiles;
        if (sourceChild instanceof File){
            sourceChild.remove();
            }
        if (sourceChild instanceof Folder){
            alert("I found a folder");
        }
    }
}

function checkFolderExists(myObj){
    var flagEx = false;
    if (myObj.exists){
        flagEx = true; //alert("myTargetFolder exists");
     } else {
        flagEx = false; //alert("myTargetFolder does NOT exist");
     }
     return flagEx;
}