Matthew 26:73

‘And after a little while those who stood by came and said to Peter, “Of a truth you also are one of them, for your speech exposes you.” '

Unfortunately for him by this time interest had been aroused and he was now under observation Thus one of the men approached him and pointed to his accent as demonstrating that he was a Galilaean, and therefore surely ‘one of them'. Peter had become an object of curiosity and he was basically saying, ‘The girl is right. You are one of them.' Peter was by this time terrified. All thoughts of loyalty had gone. (It will, however, be noted that there is no indication of any real threat. It was probably mainly all in Peter's mind).