Midnight was very near ere Malone returned to Grape Street. After tracking the manager of the bank to his lair in Golder’s Green, he had dragged him back to the bank, and searched out the thousand pound cheque, together with two others unquestionably genuine, for the sake of comparison.

“This fellow knows nothing of the circumstances in which it was changed,” said Malone. “Suppose we’ll have to look up the cashier in the morning on that point.”

Labar thrust his hand into a desk drawer and pulled out a magnifying glass. Placing the suspected cheque and another in front of him he studied them intently for a few minutes.

“Did he hold any views on whether it was a forgery or not, Bill?” he asked without looking up.

The other shook his head. “He’s a cautious Scot. You see if it is a forgery the bank will be liable. Didn’t want me to bring away the cheques at first. Someone had been telephoning him to send back all cancelled cheques to Gertstein early in the morning.”