Detectives investigating the murder of a Russian businessman have found no evidence of forced entry into his home.
Nikolai Glushkov was found dead from apparent "compression to his neck" at his home in New Malden, south-west London, on 12 March.
He was a friend of Boris Berezovsky, a critic of Vladimir Putin, and was wanted in Russia on fraud allegations.
Police reiterated they have not found a link between his death and the Skripal poisonings in Salisbury.
Counter-terrorism officers have been carrying out house-to-house inquiries near his home on Clarence Avenue and are appealing for witnesses.
Metropolitan Police Commander Clarke Jarrett said more than 400 exhibits are being processed and a number of statements have already been taken.
He said: "We have found no sign of forced entry thus far, but the forensic examination at Mr Glushkov's home continues and we expect to be there for some time.
"I must stress that there is nothing we have found in our investigation so far to suggest any link to the attempted murders in Salisbury and I would like to reassure the public in New Malden that there are no wider public health concerns in relation to this investigation."
Mr Glushkov, the former deputy director of Russian state airline Aeroflot, was jailed in 1999 for five years after being charged with money laundering and fraud.
After being given a suspended sentence for another count of fraud in 2006, he was granted political asylum in the UK in 2010 and became a critic of Russian President Vladimir Putin.
His friend Mr Berezovsky was found hanged in the bathroom of his Berkshire home in 2013 and an inquest recorded an open verdict.
Mr Glushkov said his friend had not taken his own life.