Sequelize error when using "where" and "in" on a subarray

This is my model definition:

var Tag = sequelize.define('Tag', {
    name: Sequelize.STRING
});

var Event = sequelize.define('Event', {
    name: Sequelize.STRING,
});

Event.hasMany(Tag, {as: 'tags', through: 'event_tags', foreignKey: 'eventId'});
Tag.hasMany(Event, {as: 'events', through: 'event_tags', foreignKey: 'tagId'});

In words this is: there are events and tags. Events are tagged with many tags.

I'm trying to run this query:

Event
.findAndCountAll({
    include: [{model: Tag, as: 'tags'}],
    where: {'tags.id': {in: [1,2,3,4]}},
    order: order,
    limit: pageSize,
    offset: pageSize * (page - 1),
})
.success(function(result) {

    ...
});

But I'm getting this error:

   \node_modules\sequelize\lib\dialects\abstract\query-generator.js:1134
          var logicResult = Utils.getWhereLogic(logic, hash[key][logic]);
                                                                ^
   TypeError: Cannot read property 'in' of undefined

What am I doing wrong?

I've used before the "in" expression, for example here:

 Tag
 .find({
      where: {id: {in: [1,2,3,4]}}
 }).success(...)

And it worked just fine.

I've never used the in expression with a sub-array though, as in this case. So I don't know if thats the correct way to do it.