The 43 year old suspect, a convicted sex offender named Cristian B.

Is currently in a German prison on drugs.

Offenses.

The case is being reviewed include the disappearance of a German boy in southern Portugal in 1996 of the disappearance in Germany of a five year old girl in 2015.

Our Berlin correspondent Jenny Hill has more details.

In the tranquility of the German countryside, the former home of a suspected child killer, Christiane, be owned.

This land lived here sometimes in a caravan.

The impression you get is of a rather secretive man.

Someone who came and went usually at night who didn't want to speak to the neighbors, in fact, gave the very clear impression he didn't want to be disturbed.

Police have searched this land twice in the last four years.

They found a memory stick containing child pornography but no trace of a little German girl who went missing in 2015.

Anger was five when she disappeared from a family party.

We've been told that police still suspect Christiane be of involvement in her disappearance.

There are the suspects that detectives know he had an acquaintance who worked at the complex where the party was held.

This lawyer represents in his father.

It's always when every few months or every few years new evidence is in.

In our case appears it is something between hope that his story is still alive and resignation, that she might be dead already.

Christiane Be first came to Portugal in 1995 on the run from Germany, where he'd been convicted of sexually abusing a child.

A year later, a German boy disappeared in the Al Gough German police, now reportedly looking again at the case.

More details are emerging about the man whose biography is chaotic, characterized by crime.

Christiane be drifted between Portugal and Germany in the years after Madeleine's disappearance.

For a while, he ran this shop in Branch Spike.

He's now in Kiel prison, serving a sentence for drug dealing and for the rape of a 72 year old woman.

In prior delusion.

German police believe Christian be killed Madeline McCann, but they say they still need the public's help if there to bring him to justice.