"I am off to London today," Khalid Masood reportedly told staff at the budget Preston Park Hotel in the seaside town of Brighton where he spent his final night.
Then he drove his rented Hyundai SUV about 80km to the British capital city and carried out his terror blitz on Wednesday afternoon at Westminster Bridge and the Houses of Parliament, killing four people and injuring as many as 50.
As the police scramble to find out whether Masood's murderous act was part of a wider plot, details have emerged about the terrorist.
According to the police, Masood had several aliases. He was born in Kent, in south-east England, to a black father and white mother. He had also been known as Adrian Russell Ajao, Adrian Elms and Khalid Choudry.
The 52-year-old had a violent past, chalking up convictions for assault, including grievous bodily harm, and possession of offensive weapons over the course of 20 years.
80 Distance in kilometres Khalid Masood reportedly drove, from Brighton to London, before he carried out his attack at Westminster Bridge and the Houses of Parliament.
The bodybuilding enthusiast was first convicted in 1983 of criminal damage when he was 18. In 2000, he slashed a man across the face after an argument, which landed him in jail for two years. Three years later, he stabbed a man in the nose and returned to jail for six months.
In 2005, he went to Saudi Arabia and taught English to workers at the General Authority of Civil Aviation in Jeddah, said The Sun newspaper, citing a copy of his curriculum vitae it had seen. He had described himself in his CV as "British", "friendly and approachable" and a "good listener". He also claimed to have an economics degree and started his career in sales, moving up to become a manager at Aaron Chemicals in Bodiam, East Sussex.
Some media outlets have suggested he was radicalised in Saudi Arabia, while others say it happened earlier, while he was behind bars.
Masood returned to Britain in 2009 and was reported to have worked at a college in Luton, teaching English as a foreign language.
Prime Minister Theresa May said he was known to the intelligence agency and was investigated for "violent extremism". It was thought that he came under the security service's radar after serving time. But he was "not part of the current intelligence picture", she said.
British media outlets that spoke to his previous neighbours said he recently became a grandfather, and was always seen in Islamic dress. The neighbours also described him as polite and shy, and into gardening.
Masood and his family appeared to have moved frequently in the past six years. The Telegraph newspaper said electoral roll records showed him "living in areas notorious for pockets of Islamist extremism".
He apparently lived for more than two years until 2013 in Luton, north of London, another town that has been described as a hotbed of radical Islamic activities.
The Telegraph said Masood and his family moved to Birmingham in the past year, into a flat in Winson Green. It was here that the police raided shortly after the attack.
"London isn't like it used to be," Masood reportedly told hotel staff before he left for the capital city that fateful Wednesday.
Tan Dawn Wei