- Former Russian banker German Gorbuntsov shot outside his home in east London
- Attacker was reportedly armed with a sub-machine-gun; Gorbuntsov is critically ill
- Police want to speak to taxi driver who dropped victim off shortly before attack
Police hunting the would-be killer of a former Russian banker gunned down outside his east London home have appealed for help to trace the taxi driver who dropped him off shortly before he was attacked.
German Gorbuntsov, 45, was shot several times last Tuesday evening, as he walked into an apartment block on Byng Street in the Isle of Dogs, near the Canary Wharf business district.
London's Metropolitan Police say they are treating the shooting as attempted murder. Gorbuntsov remains in a critical but stable condition in an unnamed London hospital.
Detectives say they want to speak to a cab driver who picked him up in Bishopsgate, in London's financial district, at 1900 GMT on Tuesday, and drove him to Byng Street, where he got out of the taxi shortly before 1930 GMT.
No arrests have been made and police have not revealed details of the weapon used in the attack, though Russia's Kommersant daily reported that Gorbuntsov was shot with a sub-machine-gun.
"The shooting is not thought to be gang related or linked to any other incidents" in the area, the Metropolitan Police said in a statement. "Officers retain an open mind regarding the motive for the attack at this time."
Kommersant cited Gorbuntsov's Russian lawyer, Vadim Vedenin, as saying the attack could be linked to an ongoing investigation into the attempted murder of another Russian banker, Aleksandr Antonov, in Moscow in 2009.
Gorbuntsov reportedly formerly owned banks in Russia and Moldova, a former Soviet republic which gained independence from Russia in 1991.
Russia's state news agency RIA Novosti reports that Gorbuntsov is wanted in Moldova on several charges, including an illegal bank takeover and embezzlement.
But Gorbuntsov's Moldovan lawyer Valery Andronik told Kommersant that his client believed any threat to his safety came from within Russia.
He is among a number of well-connected Russians, some of them at odds with Vladimir Putin's government, to have moved to London in recent years.
British media have drawn links between this latest potential assassination attempt and the poisoning death of a dissident former Russian spy in London in 2006.
Alexander Litvinenko, a vehement critic of President Putin, was a former KGB agent who came to Britain in 2000 after turning whistle-blower on the FSB, the KGB's successor.
He died at a London hospital November 23, 2006, after being poisoned by the radioactive material polonium-210. In a deathbed statement he blamed Putin, an accusation the Kremlin has strongly denied.
Authorities in London want Russia to extradite Andrei Lugovoi, suspected in the killing, but Russia has repeatedly refused.