SQLite Android Leaked

I've this method to read the database:

class BDUtilities

    public BDUtilities(Context context){
        this.context = context;
        this.bd = new BDHelper(context);
        this.db_reader = bd.getReadableDatabase();
        this.db_writer = bd.getWritableDatabase();
    }

     public ArrayList<Boolean> getPreferences() {
        ArrayList<Boolean> resultados = new ArrayList<Boolean>();
        if (checkBeforeUse()) {
            try {
                int user_id = getUserId();

                Cursor c = db_reader.rawQuery("select cb_save_login, cb_save_pic_after_share," +
                        "cb_upload_anonym, cb_init_cat_pref, user_id from prefs where user_id = ?", new String[] { String.valueOf(user_id) });

                if (c.getCount() > 0){
                    c.moveToFirst();
                    resultados.add(parse(c.getString(c.getColumnIndex("cb_save_login"))));
                    resultados.add(parse(c.getString(c.getColumnIndex("cb_save_pic_after_share"))));
                    resultados.add(parse(c.getString(c.getColumnIndex("cb_upload_anonym"))));
                    resultados.add(parse(c.getString(c.getColumnIndex("cb_init_cat_pref"))));
                    c.close();
                } else { c.close(); }
            }
            finally {
                //both error
                //bd.close();
                //db_reader.close(); //error:
                //01-12 06:05:36.370: E/AndroidRuntime(1681): java.lang.IllegalStateException: 
                //attempt to re-open an already-closed object: SQLiteDatabase:                   
                //data/data/com.example.photopt/databases/projeto_ddm.db
            }
        }
        return resultados;
     }

I've tried to close db_reader that has bd_reader = database.getReadableDatabase(); but has error.

This code: This doesn't return error but after some uses it shows this:

01-12 05:51:29.647: W/SQLiteConnectionPool(1762): A SQLiteConnection object for database '/data/data/com.example.photopt/databases/projeto_ddm.db' was leaked! Please fix your application to end transactions in progress properly and to close the database when it is no longer needed.