LONDON - The police report describes him as a "falling object" who lost control of his bicycle after being overwhelmed by the challenge of pedalling and waving at the same time.
So ends the mystery of how President George W. Bush collided into and injured a police officer while cycling at Gleneagles Hotel on the first day of the G8 summit.
The full explanation of how the President managed to career into a Strathclyde constable hinges on his attempt to wave and shout, "Thanks, you guys, for coming".
Anti-riot police had been deployed to the area in July last year to prevent demonstrators from entering the hotel's rear entrance, where world leaders had gathered.
The police report, obtained by Scotland on Sunday newspaper, details how raising his arm and shouting thanks triggered a case of the wobbles.
It gives a blow-by-blow account of the lead-up to the accident.
"[The unit] was requested to cover the road junction on the Auchterarder to Braco Rd as the President of the USA, George Bush, was cycling through. At about 1800 hours the President approached the junction at speed on the bicycle.
"The road was damp at the time. As the President passed the junction at speed he raised his left arm from the handlebars to wave to the police officers present while shouting, 'Thanks, you guys, for coming'.
"As he did this he lost control of the cycle, falling to the ground, causing both himself and his bicycle to strike [the officer] on the lower legs. [The officer] fell to the ground, striking his head."
The report tells how the President skidded 5m along the road after knocking down the constable, who was off duty for 14 weeks after the accident.
It reads: "The President continued along the ground for approximately 5m, causing himself a number of abrasions. The officers ... then assisted both injured parties."
The injured officer received a phone call of apology while he was on his way to Perth Royal Infirmary, where he was treated for damage to his ankle ligaments and given crutches.
The White House initially claimed the policeman had recovered within hours of the prang.
The collision could have led to a police fine and Strathclyde Police last year issued three fixed penalty notices as part of a crackdown on rogue riders.
The President's injuries - including scrapes to his hands - were, by comparison, less severe, although his dignity may have suffered.
Afterwards he shrugged off the incident, joking that he should start "acting my age".
In January 2002, Bush grazed his cheek when he fell after choking on a pretzel. Then, in June 2003, he fell off his hi-tech Segway scooter.