The veils of death

In the same house that his father had committed suicide, Dick Lamont is found brutally stabbed and dying. The last words he utters are odd: 'Caught me ... never guessed ... the seventh ... ' Lamont's sister tells the investigating detective that, just before he died, their father had entrusted her with two silken squares, embroidered with strange black lines; their purpose unknown. Was there any connection between them and the murder in the empty house?