Possible Clues:

• Unresponsive period from Disraeli, once ruffled
• Symptom of ghosting (letters 2 to 6, Spain)
• Broadcasting code in Israel prohibits communication
• Incommunicado period
• Still chasing one of the mediums? It's why the Garda won't say anything!
• Uncharacteristic quiet spell
• Does this describe quiet time by the wireless? The Garda has nothing to say