In April 2011, Satoshi Nakamoto sent what is believed to be his last email to Gavin Andresen, writing:
“I’ve moved on to other things. It’s in good hands with Gavin and everyone.”
After this, Satoshi ceased all known communication. Gavin Andresen had recently informed Satoshi that he had been invited to speak at the CIA about Bitcoin. Whether this contributed to Satoshi’s withdrawal remains a matter of speculation.