Social media users were moved to tears after a picture was shared of George HW Bush’s service dog asleep next to his coffin.
The 41st US president died at his Houston home on Friday, aged 94, and the image of Sully next to the flag-draped casket was accompanied by the caption: “Mission complete.”
Mr Bush received Sully in June to help him with issues stemming from a form of Parkinson’s disease, such as opening doors, picking up items and summoning help.
Sully will stay with the coffin until it reaches Washington DC, the site of Mr Bush’s state funeral.
The Labrador will then return to America’s VetDogs in New York before joining the Water Reed National Military Medical Centre’s Facility Dog Programme, where he will assist wounded soldiers.
The touching image of the dog staying by the former US leader’s side has been widely shared, with the president’s son Jeb tweeting “Sully has the watch.”
Another of Mr Bush’s sons, 43rd President George W Bush, wrote on Instagram: “As much as our family is going to miss this dog, we’re comforted to know he’ll bring the same joy to his new home, Walter Reed, that be brought to 41.”
Others on social media also commended Sully for his service to the former president.
Mr Bush’s state funeral takes place at Washington’s National Cathedral on Wednesday, before a private service at his longtime church in Houston on Thursday.