The paper explores the current activities of the Committee of the Parties to the Convention on the Protection of children against Sexual Exploitation and Sexual Abuse. The aim is to analyse the Parties' national legislation and legal practices regarding the provision of best interests of the child and child-friendly criminal proceedings in case of the offence where the supposed perpetrator is a person within the child's circle of trust. The paper strives to identify those areas where the Parties' national legislation and practice do not fully comply with the Convention provisions. The research has accumulated the data of Member States' surveys. The paper includes the comprehensive comparative analysis of the Parties' national legislation provisions and the scope of procedural activities, measures to be taken by the institutions and bodies that are engaged in investigation and trial. The research methodology rests on the comparative analysis of national legislations of the Member States. The paper ends up with the recommendations regarding the international trends to harmonise Member States' national legislation in line with the Convention on the Protection of Children against Sexual Exploitation and Sexual Abuse.