"George H.W. Bush, a patrician New Englander whose presidency soared with the coalition victory over Iraq in Kuwait, but then plummeted in the throes of a weak economy that led voters to turn him out of office after a single term, has died".
The former president leaves behind a long legacy in global politics.
Along with the tweet, the 41st President included a photo of himself, Sully and Bush's successor in office, Bill Clinton, the 42nd President of the United States.
Mr Bush's body is due to lie in state this week ahead of a day of national mourning. "So, we look forward to doing that, and he certainly deserves it".
David J. Phillip Pool AP
The Bushes will join other family at Joint Base Andrews for the afternoon arrival of the presidential aircraft carrying the casket, being called "Special Air Mission 41". Sometimes he appeared with the American flag, such as on the Fourth of July.
Some of the agents will also act as honorary pallbearers in Texas at the funeral home and Ellington Field, where Bush will begin his final flight back to Washington, DC. Bush's son President George W. Bush named Roberts chief justice in 2005. But the decorated war veteran is also fondly remembered for his love of fun, colorful socks.
On Sunday, the photo of the service dog lying before Bush's casket became the latest post.
The service dog was assigned to former Prez Bush back in June, and Bush family spokesman Jim McGrath says Sully - trained by the nonprofit group America's VetDogs - will be reassigned now. He will be honored during several public and private events in Houston and Washington before his burial Thursday in Texas.More news: All Blacks Sevens complete Dubai double
More news: Pakistan and India begin construction of 'corridor of peace'
More news: Was Post-Fed Chair Speech Rally a Market Overreaction?