Police went to the apartment in a Bloomsbury townhouse Wednesday afternoon, The Daily Telegraph reported. They found Margaret Mercati still alive, but she died within minutes.
The body of Robert Mercati, 63, was in another room. Investigators say he strangled his wife and then hanged himself.
Mercati served a number of prison sentences, most recently getting 10 months last year.
In his most notorious crime, he was sentenced to 18 months after using duplicate keys to steal thousands of pounds in gems from the Berkeley Hotel in Knightsbridge in 2003. He was arrested after police showed images of the theft from security cameras but the gems were never recovered.
Some neighbors said the couple, who had been married for 35 years, were clearly having problems.
One said Margaret Mercati had become increasingly depressed, rarely leaving the house in the last year or two.
"He had got very suspicious," an employee at a dry cleaner's patronized by Mercati said. "He was looking to find something or catch her out. He was a big drinker, he drank a lot."
Annette Sacker, who owns a nearby florist shop, remembered the couple as "full of life." She said she used to go on "girls' nights" with Margaret Mercati, who enjoyed Irish dancing, and her husband used to come in frequently to buy her flowers.
"He was a real character and always looked very dapper," she said. "He was smartly dressed, with the shiniest shoes, pressed trousers and often a hat."
The couple had two sons, and neighbors said Mercati enjoyed playing with his young grandson.