Berlin (CNN)Police are searching for a Tunisian man in his early 20s in connection with the Berlin Christmas market attack, German officials said Wednesday, as questions were raised about his possible ties to Islamist extremism. (...)
German penal code requires a trial within six months if an arrest warrant is issued by a judge upon request of a state attorney.
Thus, a suspect cannot be put in (investigative) arrest prior to trial unless (district) state attorney is able to make a case in court within this six month period and the prospective punishment exceeds jail time of six months by far - let's say minimum 12 months without probation.
Germany's jails have been filled up to its limits.
Thus, German state attorneys tend to be quite hesitant to seek arrest warrants. And if or when the law enforcement office really requests the incarceration of a suspect the judge in charge will finally decide whether or not an arrest is warranted.
State attorneys are civil servants and subordinates to the respective justice ministry of the federal state ( and its jurisdiction ).
It seems as if those state attorneys who don't seek arrest warrants have more chances of obtaining higher posts as well as becoming judges at higher courts with a state or in federal court.