Can a vampire tell the truth?

‘Come on Kingsteignton’ asked Roland impatiently after the silence had dragged out for several minutes. ‘It can’t be that hard to tell the truth; break the habit of the centuries and spit it out’.
Kingsteignton got up out of his chair and went and stood by the fire, kicking a smouldering log back into the flames with the tip of his highly polished shoe.
‘I have told you the truth, de Cazalrenoux; I need your help in sorting out the Romanian vampire rabble. I believe that it is to the benefit of all Old Kingdomers that they are brought to heel!’
‘Brought to heel?’ mocked Roland softly. ‘Who crowned you king of the Romanian vampires? I thought that young Vladimirescu was their leader? That he had taken over from Baron von Orloc? Not that he seems to have left London yet! Weren’t you involved somewhere in the staking of his father? And in the unleashing of the death squads?’
Kingsteignton continued to poke at the fire with his toe.
‘You have given me no reason as to why you are trying to destroy your own kind in Romania. If you were really concerned in conserving the Old Kingdom, you would not be participating in their slaughter! This wouldn’t have anything to do with this mysterious daughter of yours would it?’ asked Roland viciously.
Kingsteignton kicked at the fire harder and turned and faced Roland.
‘You seem to have compiled a lot of personal information on me’ he said heavily ‘especially for one who can’t even keep track of all the members of his own clan!’
‘I only have your word on that Kingsteignton; and your word is not something I would even risk the life of a cockroach on’ retorted Roland.
‘But I have proof, my boy’, drawled Kingsteignton. He slid his long elegant hand adorned with a strange heavy gold signet ring into his trouser pocket and pulled out a wad of tawny brown fur.
Roland felt his hackles rise, and he fought hard to not start the change process. Common belief would have it that the werewolves only changed at night during the period of the full moon, whether they wanted to or not. True this was a period of enforced change for them, but all adult werewolves could change at will, and, if they were not careful, spontaneously if they were put under stress or were in grave danger. It was a life skill that young werewolves had to master, and many had gone in to the change at the wrong time and place, sometimes with tragic consequences.
Kingsteignton tossed the wad of fur at Roland, who caught it in one hand and brought it up to his nose.
He sniffed at it delicately, his incredibly sensitive sense of smell teasing out all the different scents and signatures emanating from the fur. He imposed his iron will to stop his hand trembling as a totally new, but very familiar odour entered his nostrils. The scent was that of a very young female werewolf; this was the fur of a previously unknown member of the Clan.
Roland involuntarily growled low in his throat and bared his shining, white canines. He leapt out of his chair and in one swift movement grabbed Kingsteignton by the throat and slammed him against the wall.
‘Tell me where you got this’ he ground out ‘and this time it had better be the truth!’