Tobias Ellwood, right, with former U.S. Secretary of State John Kerry in Saudi Arabia in 2016. Ellwood's brother was killed in Bali in a terror attack in 2002, according to the AP.
The former soldier gave the police officer mouth-to-mouth and tried to stop the blood flow while waiting for ambulances to arrive in the wake of the horrifying scenes in Westminster. He remains a reservist.
The Conservative MP for Bournemouth East was born in NY and served in the Royal Green Jackets, where he reached the rank of Captain before resigning his commission to enter politics. He was then later seen heading back to his office, covered in the officer's blood.
Tobias Ellwood, the Foreign Office Minister for the Middle East and Africa, was pictured giving first aid to the wounded officer as other emergency personnel surrounded the scene.
Mr Ellwood performed mouth-to-mouth resuscitation on the officer, who later died of his injuries.
Police said at least 20 people were injured.
Tragically the officer died just hours after the blood-soaked rampage which began when a auto smashed into pedestrians on Westminster Bridge.
His brother was killed in the second of two blasts that tore through a night club.
The incident happened when an attacker in a vehicle ploughed into pedestrians on Westminster Bridge at around 2:40pm on Wednesday, before crashing into the railing of the Houses of Parliament.
About 10 yards away was the attacker who was shot dead by police after scaling the security wall toward Parliament's grounds.
It is thought multiple police officers were injured as the knifeman fought to get close to Parliament and inside the fence.