A further step has been completed in the investigations into those suspected in the Maddie case.
The accused had been subjected to identification treatment, said Hans Christian Wolters from the Braunschweig public prosecutor's office on Friday of the German Press Agency.
Such a measure essentially takes photos and records possible special features such as scars, tattoos or birthmarks, explained the spokesman for the law enforcement agency.
A few weeks ago, "Bild" reported on the 45-year-old's approval of a corresponding investigation.
The photos and information obtained should be compared, among other things, with descriptions of the perpetrators by witnesses, as prosecutor Wolters said.
The focus is not only on the German in the case of the British girl Madeleine McCann, who disappeared in Portugal in 2007.
Christian B. is also being investigated for other sex crimes, including two cases of abuse and three allegations of rape.
Detention in Oldenburg
The 45-year-old is currently serving a several-year prison sentence in Oldenburg for the rape of an American woman in Praia da Luz, Portugal, in 2005, where around a year and a half later the then three-year-old Maddie disappeared from an apartment complex.
With a view to the alleged sexual offenses, there is still a period during which the defense attorney can comment on the allegations, as prosecutor Wolters said.
This may be followed by follow-up investigations before a decision can be made on an indictment.
The suspect's defense attorney, Friedrich Fülscher, told the dpa that he did not yet have the result of the identification service.
Therefore, he could not comment on the investigative measure.
Overall, there is still no statement from the defense on the various allegations against Christian B.