Hurshid Normuradov is accused killing French wine trader Thierry Spinelli, his 30-year-old wife Olga, and their three-year-old daughter on April 20, and setting their apartment on fire to cover up traces of the crime.
The location of a second suspect in the murder has also been established.
"The investigation is currently preparing documents to request Normuradov's extradition to Russia," a spokesman for the Russian Investigation Department said. "The investigation is ongoing."
People who knew the family earlier suggested that the murder may have been committed by a group of workers who were renovating the family's apartment. They said Spinelli had an argument with the workers after they repeatedly flooded the apartment.
Spinelli, a co-founder of the Chateau le Grand Vostok winery in south Russia's Krasnodar Region, had lived in Russia for more than 10 years. His wife was a Russian national, while his daughter had dual Russian-French citizenship.
