diff --git a/crud.go b/crud.go
index 2cb3afc..1151e1c 100644
--- a/crud.go
+++ b/crud.go
@@ -37,6 +37,84 @@ func ReadDocument(db *mgo.Database, m ModelInterface, selector bson.M) error {
 // PipelineModifierFunction is a function to modify mongodb query
 type PipelineModifierFunction func(pipeline []bson.M) []bson.M
 
+func convertIDValue(v reflect.Value) reflect.Value {
+	v = reflect.ValueOf(v.Interface())
+	vKind := v.Kind() // mapVal.Kind() does not work, no idea why ;(
+	spew.Dump(v.Interface())
+	spew.Dump(vKind)
+
+	switch vKind {
+	case reflect.String:
+		return reflect.ValueOf(bson.ObjectIdHex(v.Interface().(string)))
+	case reflect.Map:
+		for _, key := range v.MapKeys() {
+			v.SetMapIndex(key, convertIDValue(v.MapIndex(key)))
+		}
+	case reflect.Slice:
+		for i := 0; i < v.Len(); i++ {
+			v.Index(i).Set(convertIDValue(v.Index(i)))
+		}
+	}
+
+	return v
+}
+
+func idToObjectID(filter interface{}) {
+	spew.Dump(filter)
+	val := reflect.ValueOf(filter)
+	switch reflect.TypeOf(filter).Kind() {
+	case reflect.Slice:
+		for i := 0; i < val.Len(); i++ {
+			idToObjectID(val.Index(i).Interface())
+		}
+	case reflect.Ptr:
+		idToObjectID(reflect.Indirect(val).Interface())
+	case reflect.Map:
+		for _, key := range val.MapKeys() {
+			if k, ok := key.Interface().(string); ok {
+				mapVal := val.MapIndex(key)
+				if mapVal.Type().Kind() == reflect.Ptr {
+					mapVal = reflect.Indirect(mapVal)
+				}
+				if k == "_id" {
+					val.SetMapIndex(key, convertIDValue(mapVal))
+				} else {
+					idToObjectID(mapVal.Interface())
+				}
+			}
+		}
+	}
+
+	/*
+		for key, data := range filter {
+			if key == "_id" {
+				if hex, ok := data.(string); ok {
+					filter[key] = bson.ObjectIdHex(hex)
+				}
+			} else {
+				switch d := data.(type) {
+				case map[string]interface{}:
+					idToObjectID(d)
+				case bson.M:
+					idToObjectID(d)
+				case []map[string]interface{}:
+					for _, s := range d {
+						idToObjectID(s)
+					}
+				case []bson.M:
+					for _, s := range d {
+						idToObjectID(s)
+					}
+				case []interface{}:
+					for _, s := range d {
+						isToObjectID(s)
+					}
+				}
+			}
+		}
+	*/
+}
+
 // ReadCollection gets the filtered collection of the model
 func ReadCollection(db *mgo.Database, results interface{}, filter bson.M, selector bson.M, offset int, limit int, sort []string, pipelineModifier PipelineModifierFunction) (err error) {
 	defer func() {
@@ -116,6 +194,10 @@ func ReadCollection(db *mgo.Database, results interface{}, filter bson.M, select
 	} else {
 		// search without pipe is faster
 
+		idToObjectID(filter)
+
+		spew.Dump(filter)
+
 		q := c.Find(filter)
 		if selector != nil {
 			q = q.Select(selector)