German police revealed Wednesday they have identified a new suspect in the disappearance of British girl Madeleine McCann in 2007, saying that the 43-year-old man may have killed her.

"In connection with the disappearance of the then three-year-old British girl Madeleine Beth McCann..., the Braunschweig public prosecutor's office is investigating a 43-year-old German citizen on suspicion of murder," said federal police in a statement.

On May 3, 2007, a few days before her fourth birthday, "Maddie" disappeared from her family's holiday apartment in the Algarve village in Portugal as her parents dined with friends at a nearby restaurant, sparking one of the biggest searches of its kind in recent years.

Despite a wide range of suspects and theories about what happened, no one has ever been convicted over her disappearance.

The suspect, who was not named by police, is serving a "long prison sentence", and has previous convictions over child sexual abuse, said Germany's federal criminal agency.

Lead investigator Christian Hoppe told ZDF television that their investigation had led police to suspect that the man was involved in the killing of Madeleine. 

He regularly lived between 1995 and 2007 in Algarve, police added, launching an appeal for information relating to two vehicles that the suspect was known to have used as well as two phone numbers.

The first is a dark coloured Jaguar XJR 6 which bore a German plate from the city of Augsburg. The second vehicle is a Volkswagen T3 Westfalia with a Portuguese plate. 

Portuguese police closed their investigation in 2008 after 14 months, which at one point implicated her parents in her abduction before their names were cleared.

British police opened their own inquiry in July 2013, but excavations in Praia da Luz yielded no evidence.