DataTables Uncaught SyntaxError: Unexpected token : - json

Question

I try to use the DataTables component with data provided by a REST API. Chrome reports the following error Uncaught SyntaxError: Unexpected token : on line 2 (see JSON below) when I use server-side data but it works if I use a text file. The setup is:
$('#table_id')
.dataTable({
"bProcessing": true,
"bServerSide": true,
"sAjaxSource": "http://mylocalhost:8888/_ah/api/realestate/v1/properties/demo",
//"sAjaxSource": "data.txt",
"sAjaxDataProp": "items",
"aoColumns": [{
"mData": "id"
}],
"fnServerData": function (
sUrl,
aoData,
fnCallback,
oSettings) {
oSettings.jqXHR = $
.ajax({
"url": sUrl,
"data": aoData,
"success": fnCallback,
"dataType": "jsonp",
"cache": false
});
}
}
}
The JSON returned by the server or in the data.txt file:
{
"iTotalRecords" : 10,
"iTotalDisplayRecords" : 10,
"sEcho" : "1",
"items" : [ {
"id" : "0"
}, {
"id" : "1"
}, {
"id" : "2"
}, {
"id" : "3"
}, {
"id" : "4"
}, {
"id" : "5"
}, {
"id" : "6"
}, {
"id" : "7"
}, {
"id" : "8"
}, {
"id" : "9"
} ]
}
Changing the sAjaxSource to data.txt works but not when the data comes from the server whereas the data are the same.