A method at a core network border element, comprising determining a capability of lawful interception, establishing a correlation between lawful interception tasks at core network border elements belonging to the same communication transaction (S931, S922-1), performing lawful interception of bearer traffic in a communication transaction (S921-2), if determined to be capable, said performing comprising detecting, at a signaling part of the core network border element, a necessity of lawful interception on the side of the core network with respect to the communication transaction, on which the executing core network border element is located, informing a bearer part of the core network border element about the necessity of lawful interception, performing, at the bearer part of the core network border element, lawful interception of bearer traffic in a communication transaction on said side of the core network, and issuing an indication on the determined capability of lawful interception to another core network border element involved in the same communication transaction, and delegating lawful interception of bearer traffic in a communication transaction to another element (S923-3), if determined to be incapable, said delegating comprising issuing an indication on the determined incapability of lawful interception to another core network border element involved in the same communication transaction. determining a capability of lawful interception, establishing a correlation between lawful interception tasks at core network border elements belonging to the same communication transaction (S931, S922-1), performing lawful interception of bearer traffic in a communication transaction (S921-2), if determined to be capable, said performing comprising detecting, at a signaling part of the core network border element, a necessity of lawful interception on the side of the core network with respect to the communication transaction, on which the executing core network border element is located, informing a bearer part of the core network border element about the necessity of lawful interception, performing, at the bearer part of the core network border element, lawful interception of bearer traffic in a communication transaction on said side of the core network, and issuing an indication on the determined capability of lawful interception to another core network border element involved in the same communication transaction, and detecting, at a signaling part of the core network border element, a necessity of lawful interception on the side of the core network with respect to the communication transaction, on which the executing core network border element is located, informing a bearer part of the core network border element about the necessity of lawful interception, performing, at the bearer part of the core network border element, lawful interception of bearer traffic in a communication transaction on said side of the core network, and issuing an indication on the determined capability of lawful interception to another core network border element involved in the same communication transaction, and delegating lawful interception of bearer traffic in a communication transaction to another element (S923-3), if determined to be incapable, said delegating comprising issuing an indication on the determined incapability of lawful interception to another core network border element involved in the same communication transaction.