Northamptonshire Police have confirmed that Chinese businessman Anxiang Du, 53, who is wanted on suspicion of murdering a family of four, has been arrested in Morocco.
Du was arrested by Moroccan authorities on Saturday and the Home Office will now undertake the responsibility around extradition procedures.
He is the prime suspect in the investigation surrounding the killings of university lecturer Jifeng Ding, his wife Ge "Helen" Chui and their two daughters Alice, 12, and Xing, 18.
The family was found stabbed to death at their home in Wootton on April 29 last year.
A spokesman for Northamptonshire Police said they did not know how long Du's extradition may take.
Officers have been been working since the arrest in Tangier on Saturday to confirm the man was in fact Du.
The spokesman added: "We have maintained regular contact with the friends and relatives of the Ding family, and have kept them informed of this latest development."
Detectives said last week they thought Du could have been evading capture in Morocco for more than a year and launched an appeal in the country.
Northamptonshire Police said he boarded a bus at London's Victoria station shortly after the family was found dead and travelled to Paris and through France and Spain before catching a ferry from the port of Algeciras to Tangier.
The journey is believed to have taken only a few days, with Du evading capture in Morocco ever since.
Du has a background in herbal medicine and police are investigating the possibility he has used that to earn a living while on the run.
He is known to have been carrying several thousand pounds in cash when he left the UK.