I've not tried fn_dblog on Express but if it is available the following will give you delete operations:

    SELECT 
    	* 
    FROM 
    	fn_dblog(NULL, NULL) 
    WHERE 
    	Operation = 'LOP_DELETE_ROWS'

Take the transaction ID for transactions you're interested in and identify the SID that initiated the transaction with:

    SELECT
    	[Transaction SID]
    FROM
    	fn_dblog(NULL, NULL)
    WHERE
    	[Transaction ID] = @TranID
    AND
    	[Operation] = 'LOP_BEGIN_XACT'

Then identify the user from the SID:

    SELECT
    	*
    FROM 
    	sysusers
    WHERE
    	[sid] = @SID