The Royal Embassy of Saudi Arabia in London says that the Westminster attacker was in the country three times and taught English there.
A statement released late Friday says Khalid Masood taught English in Saudi Arabia from November 2005 to November 2006 and again from April 2008 to April 2009.
The embassy says he had a work visa. It says he returned for six days in March 2015.
The embassy says he wasn't tracked by Saudi security services and didn't have a criminal record there.
Before taking the name Masood, the attacker was known as Adrian Elms. He was known for having a violent temper in England and had criminal convictions.
Masood drove his rented SUV across the crowded Westminster Bridge on Wednesday, striking pedestrians. Then he jumped out and attacked police officer Keith Palmer, who was guarding Parliament, fatally stabbing him before being shot dead by police.
Islamic State claimed responsibility for the attack, which killed three people and injured 40.
Masood, who at 52 is considerably older than most extremists who carry out bloodshed in the West, had an arrest record dating to 1983. The violence came later, first in 2000 when he slashed a man across the face in a pub parking lot in a racially charged argument after drinking four pints, according to a newspaper account.
Hundreds of British police have been working to determine his motives and possible accomplices. Two people remain in custody for questioning. They are two men, aged 27 and 58, who were arrested in the central English city of Birmingham, where Masood was living. Authorities haven't charged or identified the two men. Others who were arrested in connection with the investigation have been released.
Details about how he became radicalized aren't clear. His time in Saudi Arabia may provide clues. He was also jailed in Britain and may have become exposed to radical views while an inmate.
Masood's last conviction was in 2003, also involving a knife attack. It's not clear when he took the name Masood, suggesting a conversion to Islam.
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