Police investigating the murder of a shopkeeper who was stabbed to death at his newsagents in north-west London for a "few pounds worth of coins", have arrested a man.

Ravi Katharkamar was opening his shop in Pinner, near Harrow, last Sunday morning when he was knifed. The 54-year-old's cash register was stolen.

A passerby found the shopkeeper collapsed inside the building and called the emergency services, but he was pronounced dead at the scene.

The unnamed 44-year-old suspect was arrested in Harrow, London's Metropolitan Police said.

“This was a vicious and unwarranted attack on a completely innocent man," said detective chief inspector Simon Stancombe. "Ravi’s attacker got away with a few pounds worth of coins, but he leaves behind a family utterly devastated and a close-knit community asking who could do such a thing.

London street photography – exploring the UK's capital Show all 21 1 /21 London street photography – exploring the UK's capital London street photography – exploring the UK's capital Regent Street, London Angela Christofilou London street photography – exploring the UK's capital West Norwood, London Angela Christofilou London street photography – exploring the UK's capital On the bus, Central London Angela Christofilou London street photography – exploring the UK's capital Central London Angela Christofilou London street photography – exploring the UK's capital Brick Lane, London Angela Christofilou London street photography – exploring the UK's capital Oxford Street, London Angela Christofilou London street photography – exploring the UK's capital Rush hour, London Underground Angela Christofilou London street photography – exploring the UK's capital Brick Lane, London Angela Christofilou London street photography – exploring the UK's capital On the bus through London Angela Christofilou London street photography – exploring the UK's capital High Street Kensington, London Angela Christofilou London street photography – exploring the UK's capital Whitechapel, London Angela Christofilou London street photography – exploring the UK's capital Rush hour, Oxford Circus Station Angela Christofilou London street photography – exploring the UK's capital Brick Lane, London Angela Christofilou London street photography – exploring the UK's capital Soho, London Angela Christofilou London street photography – exploring the UK's capital Shoreditch, London Angela Christofilou London street photography – exploring the UK's capital Trafalgar Square, London Angela Christofilou London street photography – exploring the UK's capital Finsbury Park, London Angela Christofilou London street photography – exploring the UK's capital Charing Cross road, London Angela Christofilou London street photography – exploring the UK's capital Trafalgar Square, London Angela Christofilou London street photography – exploring the UK's capital Shoreditch, London Angela Christofilou London street photography – exploring the UK's capital Hackney, London Angela Christofilou

“The attacker fled with a shop till – have you found this discarded or seen someone in possession of a shop till who wouldn’t normally have one? Do you know someone trying to use lots of loose change since Sunday morning?

“I am also keen to hear from anyone who has information about a black Vauxhall Astra that the attacker used to drive away from the scene. This was parked in Cecil Park prior to the murder and was drive off at speed, south down Cecil Park immediately after the attack. If you saw this car, or have seen a black Vauxhall Astra abandoned, please contact my team.”

Ravi Katharkamar was stabbed to death at his newsagents as he opened the shop on Sunday (Met Police handout)

Officers remain in the area and are available should residents have concerns or information they wish to pass on.