3. States Parties shall endeavour to cooperate within their means to respond to offences covered by this Convention committed through the use of modern technology. Article 49. Joint investigations States Parties shall consider concluding bilateral or multilateral agreements or arrangements whereby, in relation to matters that are the subject of investigations, prosecutions or judicial proceedings in one or more States, the competent authorities concerned may establish joint investigative bodies. In the absence of such agreements or arrangements, joint investigations may be undertaken by agreement on a case-by-case basis. The States Parties involved shall ensure that the sovereignty of the State Party in whose territory such investigation is to take place is fully respected. Article 50. Special investigative techniques 1. In order to combat corruption effectively, each State Party shall, to the extent permitted by the basic principles of its domestic legal system and in accordance with the conditions prescribed by its domestic law, take such measures as may be necessary, within its means, to allow for the appropriate use by its competent authorities of controlled delivery and, where it deems appropriate, other special investigative techniques, such as electronic or other forms of surveillance and undercover operations, within its territory, and to allow for the admissibility in court of evidence derived therefrom. 2. For the purpose of investigating the offences covered by this Convention, States Parties are encouraged to conclude, when necessary, appropriate bilateral or multilateral agreements or arrangements for using such special investigative techniques in the context of cooperation at the international level. Such agreements or arrangements shall be concluded and implemented in full compliance with the principle of sovereign equality of States and shall be carried out strictly in accordance with the terms of those agreements or arrangements. 3. In the absence of an agreement or arrangement as set forth in paragraph 2 of this article, decisions to use such special investigative techniques at the international level shall be made on a case-by-case basis and may, when necessary, take into consideration financial arrangements and understandings with respect to the exercise of jurisdiction by the States Parties concerned. 4. Decisions to use controlled delivery at the international level may, with the consent of the States Parties concerned, include methods such as intercepting and allowing the goods or funds to continue intact or be removed or replaced in whole or in part. 41