A £20,000 reward has been offered to help trace a Portuguese man who police fear has been murdered.
Mr Marques' flat was found unlocked
Alexandre Marques, 61, of Notting Hill Gate, west London, was last heard from on 16 October last year.
Officers are appealing for information about a man caught on CCTV using Mr Marques' cash cards in west London, in the days after he vanished.
Det Ins Tim Dobson said Mr Marques' family worries he is dead. His flat was found empty after he disappeared.
"His family and friends have heard nothing from him for weeks", he said.
'Reliable and punctual'
"They do not deserve to live for their rest of their lives without knowing what has become of him. Someone must be able to help us with our inquiries."
Last October Mr Marques' flat in Clanricarde Gardens was discovered empty, and unlocked, and his keys, white mac, Portuguese passport and wallet containing debit and credit cards, were missing.
The next day he failed to turn up at the Arts club in Mayfair where he worked as a waiter.
Police, who are treating his disappearance as a murder investigation, said it was uncharacteristic for him to leave his door unlocked and he was reliable and punctual.
A few days later a man was seen on CCTV trying to withdraw money from these accounts from banks in Willesden Green and Cricklewood Broadway.
The suspect was wearing dark trousers with red writing up the sides and a reflective light patch at the bottom of each leg.
Police are also urging members of the gay and lesbian community, who have failed to report an assault or robbery, to contact them.