27/07/2023, 22:38 CURIA - Documents 106 The Court stated, in that regard, that, while the objective evidence may vary according to the nature of the measures taken for the purposes of prevention, investigation, detection and prosecution of serious crime, the persons thus targeted may, in particular, be persons who have been identified beforehand, in the course of the applicable national procedures and on the basis of objective and non-discriminatory factors, as posing a threat to public or national security in the Member State concerned (judgment of 5 April 2022, Commissioner of An Garda Síochána and Others, C‑140/20, EU:C:2022:258, paragraph 77). 107 Member States thus have, inter alia, the option of imposing retention measures targeting persons who, on the basis of such an identification, are the subject of an investigation or other measures of current surveillance or of a reference in the national criminal record relating to an earlier conviction for serious crimes with a high risk of reoffending. Where that identification is based on objective and nondiscriminatory factors, defined in national law, targeted retention in respect of persons thus identified is justified (judgment of 5 April 2022, Commissioner of An Garda Síochána and Others, C‑140/20, EU:C:2022:258, paragraph 78). 108 Secondly, a targeted measure for the retention of traffic and location data may, at the choice of the national legislature and in strict compliance with the principle of proportionality, also be set using a geographical criterion where the competent national authorities consider, on the basis of objective and non-discriminatory factors, that there exists, in one or more geographical areas, a situation characterised by a high risk of preparation for or commission of serious criminal offences. Those areas may include places with a high incidence of serious crime, places that are particularly vulnerable to serious crime, such as places or infrastructure which regularly receive a very high volume of visitors, or strategic locations, such as airports, stations, maritime ports or tollbooth areas (judgment of 5 April 2022, Commissioner of An Garda Síochána and Others, C‑140/20, EU:C:2022:258, paragraph 79 and the case-law cited). 109 It should be borne in mind that, according to that case-law, the competent national authorities may adopt, for areas referred to in the preceding paragraph, a targeted measure of retention using a geographic criterion, such as, inter alia, the average crime rate in a geographical area, without that authority necessarily having specific indications as to the preparation or commission, in the areas concerned, of acts of serious crime. Since a targeted retention using that criterion is likely to concern, depending on the serious criminal offences in question and the situation specific to the respective Member States, both the areas marked by a high incidence of serious crime and areas particularly vulnerable to the commission of those acts, it is, in principle, not likely moreover to give rise to discrimination, as the criterion drawn from the average rate of serious crime is, in itself, entirely unconnected with any potentially discriminatory factors (judgment of 5 April 2022, Commissioner of An Garda Síochána and Others, C‑140/20, EU:C:2022:258, paragraph 80). 110 In addition and above all, a targeted measure of retention covering places or infrastructures which regularly receive a very high volume of visitors, or strategic places, such as airports, stations, maritime ports or tollbooth areas, allows the competent authorities to collect traffic data and, in particular, location data of all persons using, at a specific time, a means of electronic communication in one of those places. Thus, such a targeted retention measure may allow those authorities to obtain, through access to the retained data, information as to the presence of those persons in the places or geographical areas covered by that measure as well as their movements between or within those areas and to draw, for the purposes of combating serious crime, conclusions as to their presence and activity in those places or geographical areas at a specific time during the period of retention (judgment of 5 April 2022, Commissioner of An Garda Síochána and Others, C‑140/20, EU:C:2022:258, paragraph 81). 111 It should also be noted that the geographic areas covered by such a targeted retention measure may and, where appropriate, must be amended in accordance with changes in the circumstances that justified their selection, thus making it possible to react to developments in the fight against serious crime. The Court has held that the duration of those targeted retention measures described in paragraphs 105 to 110 above must not exceed what is strictly necessary in the light of the objective pursued and the circumstances justifying them, without prejudice to the possibility of extending those measures should such retention continue to be necessary (judgments of 6 October 2020, La Quadrature du Net and https://curia.europa.eu/juris/document/document_print.jsf;jsessionid=A4432EEFFE3535A201E714AE6441EE66?mode=DOC&pageIndex=1&docid=265881… 22/28