Investigation 2

Shaughnessy bent down and whispered to his senior.

 "Looks like he came in through that window, chief," he said.

 Delbury, who was busily examine the contents of the wallet, shrugged and told his second to go over and have a look at it.

 But as Harper walked across he was cut short by an expression from Delbury in which amazement, incredulity and utter bewilderment were all blended. "Great heavens, Mick, look here!"

 Delbury had just open a concealed flap in the wallet and taken something out.

 Shaughnessy picked the card up.

 "That's the thirty-sixth I've seen like that," he said quietly.. 

 "And it's the first one that wasn't addressed to the Yard,"

 Delbury flicked the card over. It was addressed to Willard Lyall, Esq., at his house at Highgate. The post-mark was a smudgy bodge of ink and indecipherable.

 Shaughnessy took it again and studied it critically. His special