Inquiries in parliaments and under the Freedom of Information Act show the amount of secret text messages to find out the whereabouts of telephones and their owners. Police use the method in real time for arrests, while secret services create longer-term movement profiles with it.
„Silent SMS“ are text messages whose reception is not indicated by the mobile phone. However, they generate a communication process that is logged by the telephone providers. With a court order, security authorities query this data record. Police and secret services are interested in the radio cells in which the phones are located. In this way, they obtain the location and a movement profile of the persons concerned.
For some years now, biannual inquiries to the German government have documented that the figures for „silent SMS“ at the Federal Criminal Police Office (BKA) and the Federal Police are at a similar level. The highest value for both authorities together was in the first half of 2016 at around 138,000, the lowest in the first half of 2019 at around 26,000. Subsequently, the figures have more than doubled again, the Federal Ministry of the Interior announced last week.
Court ruling two years ago
A reason for the significant slump last year is not known, but it could be the consequences of a court ruling. Two years ago, the Federal Court of Justice declared the use of „silent SMS“ and the collection of location data generated from it to be legal for the first time, thus taking the wind out of the sails of critics. The complaining lawyer, Lukas Theune, had argued that „silent SMS“ could not be based on § 100a of the Code of Criminal Procedure, since the location data is not generated secretly by the users who are being tapped, but by the police.
However, this contradicts the principle that tapping telecommunications must be a passive process in Germany. The judges agreed with this, but ruled that a different paragraph can be applied. Since then, „silent SMS“ may only be justified by § 100i, which also regulates the use of IMSI catchers. Like the „silent SMS“, IMSI catchers are used to determine the location of a mobile phone.
About 400 „silent SMS“ per measure
It is striking that the Federal Police always send more „silent SMS“ than the Federal Criminal Police. One reason could be that the method is popular especially for arrests. This was also explained by the Ministry of the Interior in North Rhine-Westphalia a few years ago in an answer to a parliamentary question by the Pirate Fraction. According to this, „silent SMS“ are used there to determine in almost real time the whereabouts of persons who are wanted for arrest.
In fact, police „silent SMS“ are used mainly in the 16 federal states. This is evidenced by some responses to Freedom of Information requests. According to this, the police authorities in Schleswig-Holstein alone send as many locating impulses as the Federal Criminal Police and the Federal Police together (2019: 112,354, 2018: 111,628). The secret text messages in Schleswig-Holstein were used in 271 measures in 2019. This means that around 400 „silent SMS“ are sent per investigation.
High figures in Berlin, Hamburg and North Rhine-Westphalia
Not surprisingly, the figures are significantly higher in metropolitan areas such as Berlin and Hamburg, but also for North Rhine-Westphalia, Germany’s most populous state. In the capital, the police sent 336,569 „silent SMS“ last year, and even 447,972 the year before. For Hamburg, the figures are lower, but at a similar level. In North Rhine-Westphalia they are only known until 2016, when around 179,000 „silent SMS“ were sent. However, this was by far the lowest figure since 2007.
Some federal states have not responded to the Freedom of Information requests. All that is known, therefore, is that the police in Rhineland-Palatinate send around 100,000 silent text messages every year, and that Brandenburg is at the bottom of the league with around 20,000 and Mecklenburg-Western Pomerania with 2,682 (figure for 2018).
Much use by the Federal Secret Service
However, little is known about the extent to which the secret services in the federal states send „silent SMS“. Where the figures were communicated in answers to parliamentary questions, it is shown that the state offices for the protection of the constitution very rarely use this method. This is different, however, in the case of the Federal Office for the Protection of the Constitution (BfV), for which the figures of recent years document a steady increase in „silent SMS“.
The statistics reveal further anomalies. It is clear, for example, that peak values were reached in the years 2016 to 2018. It can be assumed that the domestic secret service of the Confederation uses „silent SMS“ (in contrast to the police) for secret observation. Presumably there are also many more people targeted than by the police. For example, in order to determine whether a „dangerous person“ is leaving his or her place of residence or the country, it is sufficient for the BfV to send an hourly or daily „silent SMS“.
Precisely because trends can be read from the half-yearly statistics, the Federal Ministry of the Interior has meanwhile classified the figures for the BfV as secret. The reason given for this is that the information is particularly in need of confidentiality, as „regular half-yearly replies […] can condense individual pieces of information into a comprehensive situational picture“.
Image: Silent SMS at Police in Berlin.