24. From requirements (that were expressed e.g. in the decision in the case of Isayeva, Yusupova and Bazayeva v Russia from 24 February 2005, No. 57947/00, § 209-213) in this case the Constitutional Court in this case finds a lack of carefulness and thoroughness in the investigation. In this case we cannot ignore important commitments of the Czech Republic arising from EU law, and especially from EU Parliament and Council Directive No. 2011/36/EU on preventing and combating trafficking in human beings and protecting its victims, and replacing Council Framework Decision 2002/629/SVV. The mentioned directive sets out in its preamble – among other things – the following: ‘Trafficking in human beings is a serious crime, often committed within the framework of organised crime, a gross violation of fundamental rights and explicitly prohibited by the Charter of Fundamental Rights of the European Union. Preventing and combating trafficking in human beings is a priority for the Union and the Member States.’ (Article 1); ‘More rigorous prevention, prosecution and protection of victims’ rights are major objectives of this Directive. This Directive also adopts contextual understandings of the different forms of trafficking and aims to ensure that every form of tracking is tackled by means of the most efficient measures.’ (Article 7); ‘This Directive respects fundamental rights and observes the principles recognised in particular by the Charter of Fundamental Rights of the European Union and especially human dignity, the prohibition of slavery, forced labour and trafficking in human beings, the prohibition of torture and inhuman or degrading treatment or punishment, the rights of the child, the right to liberty and security, freedom of expression and information, the protection of personal data, the right to an effective remedy and to a fair trial and the principles of the legality and proportionality of criminal offences and penalties. In particular, this Directive seeks to ensure full respect for those rights and principles and must be implemented accordingly.’ (Article 33) In accordance with this, the directive contains measures ‘to ensure the success of investigations and prosecutions of human trafficking offences’ (Article 15). The prohibition of slavery and the performance of forced or compulsory labour is also set out in Article 5 of the Charter. The Czech Republic’s commitments under international law were recently broadened, when the United Nation’s Convention Against Transnational Organised Crime (No. 75/2013 Coll. of International Treaties) and the Protocol to Prevent, Suppress and Punish Trafficking in Persons, Especially Women and Children, that supplements the aforementioned convention (No. 18/2015 Coll. of International Treaties) came into effect in the CR.