Garvington did as he was asked reluctantly.  “Though I don’t see why Jarwin can’t supply his own motors,” he grumbled, “and ten to one he’ll only put an advertisement in the newspapers.”

“As if Mother Cockleshell ever saw a newspaper,” retorted his sister.  “Oh, thank you, Freddy, you are good,” she went on when he handed her the letter in a newly addressed envelope; “no, don’t go, I want to speak to you about Mr. Silver.”

Garvington threw himself with a growl into a chair.  “I don’t know anything about him except that he’s my tenant,” he complained.

“Then it is time you did.  Perhaps you are not aware that Mr. Silver tried to blackmail me.”

“What?” the little man grew purple and exploded.  “Oh, nonsense!”

“It’s anything but nonsense.”  Agnes rose and went to her desk to get the forged letter.  “He came to me a long time before Christmas and said that Chaldea found this,” she flourished the letter before her brother’s eyes, “in Hubert’s tent when he was masquerading as Hearne.”

“A letter?  What does it say?” Garvington stretched out his hand.

Agnes drew back and returned to her seat by the fire.  “I can tell you the contents,” she said coolly, “it is supposed to be written by me to Noel and makes an appointment to meet him at the blue door on the night of Hubert’s death in order to elope.”

“Agnes, you never wrote such a letter,” cried Garvington, jumping up with a furious red face.

His sister did not answer for a moment.  She had taken the letter just written to Jarwin by Garvington and was comparing it with that which Miss Greeby had extorted from Silver.  “No,” she said in a strange voice and becoming white, “I never wrote such a letter; but I should be glad to know why you did.”

“I did?” Garvington retreated and his face became as white as that of the woman who confronted him, “what the devil do you mean?”

“I always knew that you were clever at imitating handwriting, Freddy,” said Agnes, while the two letters shook in her grasp, “we used to make a joke of it, I remember.  But it was no joke when you altered that check Hubert gave you, and none when you imitated his signature to that mortgage about which he told me.”

“I never—­I never!” stammered the detected little scoundrel, holding on to a chair for support.  “I never—­”

“Spare me these lies,” interrupted his sister scornfully, “Hubert showed the mortgage, when it came into his possession, to me.  He admitted that his signature was legal to spare you, and also, for my sake, hushed up the affair of the check.  He warned you against playing with fire, Freddy, and now you have done so again, to bring about his death.”

“It’s a damned lie.”

“It’s a damned truth,” retorted Agnes fiercely.  “I got you to write the letter to Mr. Jarwin so that I might compare the signature to the one in the forged letter.  Agnes Pine in one and Agnes Pine in the other, both with the same twists and twirls—­very, very like my signature and yet with a difference that I alone can detect.  The postscript about the motor I asked you to write because the word occurs in the forged letter.  Motor and motor—­both the same.”