In the case of MM , British police, in the form of the Metropolitan police have not decided that MM is anything other than missing.What may not be sufficient evidence in Germany may be sufficient in another country?
In England, because it concerns an English child.
Or perhaps HB in Ireland because of her rape case?
They would need to determine for themselves what crime had been committed and who the likely perpertrator was before they could sumit their findings to the CPS, who in turn would need to decide if there was a case to answer before applying for extradition.