The sick murderer used WhatsApp mere moments before mowing down pedestrians and stabbing PC Keith Palmer, leaving 4 dead and 40 injured in his wake.
A screen grab of Masood’s WhatsApp profile shows the killer was using the app at 14:37, although it is unclear if he was messaging people in relation to his impending act of terror or just checking the messaging service.
It comes as police crackdown on the terrorist’s last movements in a huge counter-terror mission codenamed Operation Classific.
Police will struggle to track his last messages, as WhatsApp use high level encryption which stop hackers and security services alike from reading anything a user sends.
It comes as police crackdown on the terrorist’s last movements
But Scotland Yard have said raids the day following the attack resulted in “significant arrests” – with police currently holding 11 people in relation to his heinous terror attack.
Security services are hoping to discover if Masood, born Adrian Russell Ajao and also known as Adrian Elms, acted alone or as part of a network of terror tyrants.
Isis claimed Masood had acted as a “soldier” of the death cult, but it is currently unclear if his horrific actions were ordered by the jihadi extremists or merely inspired by their actions.
Meanwhile a smirking terror suspect with links to Saudi Arabia was held by police amid nationwide swoops on possible accomplices of the Westminster terrorist.
London mourns terror attack at vigil Fri, March 24, 2017
The world grieves after an attacker killed three people and injured about 40 near parliament in London.
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Floral tributes are left after the vigil in Trafalgar Square, London to remember those who lost their lives in the Westminster terrorist attack
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Scotland Yard have said raids the day following the attack resulted in 'significant arrests'
The man, said to be a father-of-three, shocked neighbours by grinning as he was led away after an armed raid on his £240,000 semi-detached home.
He was among 11 people arrested during raids on 20 properties in the wake of the terror attack.
The suspect seemed unconcerned by the raid on his Birmingham home, which saw an armed police officer wearing a balaclava and helmet train an assault rifle on the windows.
It is believed Masood has been seen in past months visiting the property. A battering ram was used to gain entry to the house and a silver BMW was later taken away for examination.
Isis claimed Masood had acted as a 'soldier' of the death cult
Flowers have been laid down to remember those who died in the attack
Neighbours told how the man who rented the property used to have late night visitors and had a “creepy smile”.
One said: “I went to my window and there were three cops with guns running up to the back window. There was shouting and screaming for ages. I couldn’t hear what they were saying but it was loud. It sounded like there were loads of people in there.”
One local resident said the man, thought to be in his 40s or 50s, had lived at the address for about a year.
She added: “The man they led away was put in a police van and he had a big smirk on his face when they took him away.”