Hassan Abdollianpour said on Wednesday that the audio includes final exchanges between the Dena, a US naval vessel and Sri Lanka’s shipping and ports authorities.
“In this conversation, it is stated that ‘we are not military, we are not armed and we have come for training,’ and the Sri Lankan side also confirms this,” he added.
He stressed the importance of getting access to the final communications of the Dena in order to prepare an accurate legal case and appropriate defense regarding the criminal attack.
He noted that the recordings were obtained following extensive efforts and have also been used in a documentary.
“Not only was no assistance provided, but a second attack was also carried out,” he said.
The Dena, a Moudge-class frigate, was torpedoed and sunk by the US Navy submarine USS Charlotte in international waters off the coast of Galle, Sri Lanka, on March 4.
The vessel was returning home after participating in the International Fleet Review 2026 naval exercise hosted by India — a multinational gathering to which Iran had been officially invited.
The frigate was approximately 19 nautical miles off the coast of Galle, Sri Lanka, when it was struck by a Mark 48 torpedo fired from the US Navy’s Los Angeles-class submarine USS Charlotte.
The vessel was unarmed at the time, with 136 crew members on board, 104 of whom were martyred and 32 injured.
Speaking at a ceremony in the northern province of Gilan last week, Abdolianpour said the case concerning the martyrs of the Dena is being pursued “firmly and decisively.”
He noted that the Center for Lawyers of the Judiciary has compiled extensive documentation for use in both domestic and international legal proceedings.
According to the official, around 130,000 pages of expert assessments related to war incidents and damages have been prepared with the cooperation of nearly 19,000 experts.
Abdolianpour noted that such efforts were not intended solely for use in domestic courts, but were also aimed at providing standardized evidence for pursuing the matter before international courts and legal bodies.
Back in March, Chief of Iran’s Judiciary Gholamhossein Mohseni-Eje'i denounced the US Navy’s deadly attack on the Dena destroyer as a violation of all international conventions, particularly those governing international maritime law.
He emphasized that Iran will "certainly and seriously" prosecute the criminal US regime for the "outrageous crimes," particularly the martyrdom of Iranian sailors far away from their homeland.