German prosecutors investigating a new suspect in a major breakthrough say they believe Madeleine McCann is dead.

The public prosecutor made the announcement today in a press conference, the night after revealing a new key suspect.

The prosecutors in the case are giving a major update after announcing they are treating a

The authorities are investigating a 43-year-old German man on suspicion of murder.

"The public prosecutor's office in Braunschweig is investigating a 43-year-old German national on suspicion of murder.

"From this you can see that we assume that the girl is dead," Braunschweig state prosecutor Hans Christian Wolters told media during a press conference on the developments in Germany today.

Police are probing the child's disappearance  in Portugal

It is understood the man at the centre of the probe is child sex offender Christian Stefan Brueckner.

German newspaper Braunschweiger Zeitung reported the suspect was carrying out a seven-year prison sentence for the rape of a 72-year-old American woman in Portugal in 2005.

The newspaper said he was convicted of the offence in Braunschweig district court in December last year.