Howard S. Levie, “The Indo-Pakistani Agreement of August 28, 1973” The American Journal of International Law, Vol. The treaty was signed by the foreign ministers of India, Pakistan and Bangladesh in New Delhi after the Simla agreement.  Repatriation was an important step in reconciliation between Bangladesh and Pakistan. The two countries began diplomatic relations in 1974. In Bangladesh, many repatriated officials have been reported. Judge Abdus Sattar, Bangladesh`s 9th President, was a remarkable example. Many repatriated military personnel served in the leadership of Bangladesh`s armed forces, including Rear Admiral Mahbub Ali Khan and Lieutenant-General Muhammad Mahbubur Rahman. Geoffrey Robertson QC, who served as chairman of the UNITED Nations War Crimes Tribunal in Sierra Leon, rightly set the context for the tripartite agreement in 2015 in a report entitled “REPORT ON THE INTERNATIONAL CRIMES TRIBUNAL OF BANGLADESH” by saying that the Holocaust came from Bangladesh before the world had the will to intervene in distant countries of little knowledge of the major powers. SaminaFakhruddin, “Pakistan`s relationship with India and Bangladesh,” Pakistan Horizon, Vol. XXVII No.2, 1974. After the surrender of the Pakistani army, nearly 93,000 Pakistani soldiers and civilians were transferred to India as prisoners of war.
On 21 December 1971, the UN Security Council adopted a resolution calling on the parties to respect the Geneva Convention and not to bind conditions to the repatriation of prisoners of war. Article 118 of the Geneva Convention (1949) stipulates that prisoners of war must be repatriated immediately after the end of hostilities. It also provides that the authorities are required to draw up a repatriation plan. India stated that the Pakistani army had surrendered to the joint command of India and Bangladesh and that it was therefore not India`s jurisdiction to recover the prisoners of war themselves. On the other hand, Sheikh Mujib-your-Rahman had stated that he would not participate in any bilateral or trilateral meetings unless Bangladesh had been recognized by Pakistan. On 28 August 1973, India and Pakistan signed an agreement in Delhi for the repatriation of 93,000 civilian and military prisoners to Pakistan. Bengalis in Pakistan should be repatriated to Bangladesh. Mujib your Rahman clung to his request to try 195 war criminals. Bhutto insisted that Pakistan would not recognize Bangladesh until all prisoners of war were released.
Pakistan`s recognition of Bangladesh in February 1974 led to a rapprochement between the two countries. A tripartite agreement between India-Pakistan-Bangladesh, signed in April 1974, resolved all contentious issues related to the 1971 war and also paved the way for the return of 195 war criminals. The last group of prisoners of war arrived in Lahore in April 1974. Delhi Agreement www.genocidebangladesh.org/?p=196 But Bangladesh colored the agreement because Pakistan held 203 Bangladeshi officials hostage for its 195 high-ranking officers. It also made the repatriation of four Lakh-Bangladeshis uncertain and imposed strong international pressure on Bangladesh. The treaty came into force on August 8, 1973 and expired on July 1, 1974. Under the agreement, UNHCR oversaw the repatriation of citizens from Bangladesh and Pakistan. According to the UN, 121,695 Bengalis have been transferred from Pakistan to Bangladesh. Among them are senior Bengal officials and the military. 108,744 civilians and non-Bengali officials were transferred from Bangladesh to Pakistan.  India released 6,500 Pakistani PoWs, most of whom were transported by train to Pakistan.
In 1974, General Niazi was the last Pakistani officer to be symbolically returned by the Wagah border.  Simla agreement under www.mea.gov.in/in-focus-article.htm?19005/Simla+Agreement+July+2+1972.