grounds for the interference are proportionately restricted in the individual case. § 20l
BKAG, however, only partially ensures that this is the case.
b) § 20l sec. 1 nos. 1 to 4 BKAG provides different grounds for interferences with regard to different addressees. Not all of them satisfy the constitutional requirements.
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The authorisation to carry out surveillance measures against those persons deemed
to be responsible under police laws pursuant to § 20l sec. 1 no. 1 BKAG does not
raise constitutional concerns as it in fact also aims to protect qualified legal interests
and has the sole purpose of providing protection against imminent dangers.
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However, in contrast, the not specifically limited extension of telecommunications
surveillance under § 20l sec. 1 no. 2 BKAG to also cover persons regarding whom
certain facts justify the assumption that they are preparing terrorist crimes is not compatible with the Constitution. The provision, which shifts interference powers beyond
the prevention of a specific threat to an earlier stage with the aim of preventing criminal offences, violates, given its ill-defined open phrasing, the principle of legal certainty and is disproportionately broad. In this respect, the same considerations as developed with regard to § 20g sec. 1 no. 2 BKAG (see above, C V 1 d) apply here, too.
The marginally different formulations of the two provisions do not imply any difference
in substance. This is also clarified by the Act’s explanatory memorandum that partially paraphrases the content of § 20l sec. 1 no. 2 BKAG by using those words that were
also used by the legislature in § 20g sec. 1 no. 2 BKAG (cf. BTDrucks 16/10121, p.
31). The same applies insofar as § 20l sec. 2 BKAG contains a reference to that provision.
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In contrast, the possibility of extending telecommunications surveillance to also cover messengers pursuant to § 20l sec. 1 nos. 3 and 4 BKAG is, when interpreted in
conformity with the Constitution, compatible with Art. 10 sec. 1 GG. The provision,
formulated closely in line with § 100a sec. 3 Code of Criminal Procedure (Strafprozessordnung – StPO), is sufficiently open to interpretation and satisfies the requirements of the principle of legal certainty. Like the rules on contacts and accompanying persons set out in § 20b sec. 2 no. 2 BKAG, this provision does not allow
indiscriminately extending surveillance measures to all persons that have exchanged
messages with the target person, but rather requires that there be specific grounds –
that are to be set forth in the order accordingly – indicating that the target person is involving the messenger in the realisation of a criminal offence and that the latter is thus
particularly closely linked to a crime or threat.
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c) The additional further conditions under which § 20l sec. 2 BKAG allows, subsidiarily, telecommunications surveillance at the source do not raise effective constitutional concerns. […]
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d) Procedurally, and in accordance with the constitutional requirements, �� 20l sec. 3
BKAG sets out the requirement of a judicial order (cf. BVerfGE 125, 260 <337 and
338>). However, it lacks a statutory rule that stipulates – as required under constitu-
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