Three Iranians imprisoned in Thailand for a botched 2012 bomb plot were transferred back to Iran, Thai officials said on Thursday after Tehran freed an Australian academic jailed for more than two years on a charge of spying. Thai officials refused to say whether the transfer was linked to the release of Kylie Moore-Gilbert, who Iranian state TV said was freed in exchange for three Iranians held abroad. Chatchom Akapin, Thailand's deputy attorney general, told Associated Press that Thai authorities had approved the transfer of the prisoners under an agreement with Iran. “These types of transfers aren’t unusual," he said. “We transfer prisoners to other countries and at the same time receive Thais back under this type of agreement all the time.” Flight data obtained by AP showed the plane filmed on the tarmac at Tehran airport during a reception for the freed Iranians had twice flown from Bangkok to Tehran, and then on to Doha, Qatar. The plane's tail number links it to an Australian private airline called Skytraders, which describes itself as a “principal provider of air services to government”. An employee at the company declined to comment when contacted by AP. The bomb plot of the three Iranians was exposed in 2012 when an accidental explosion blew apart the Bangkok villa where they were staying. Israeli and Thai officials said the plot was aimed at Israeli diplomats in Bangkok, although Iran denied the allegations and the men were never charged with terrorism. Two of the men, Saeid Moradi and Mohammad Kharzei, were convicted in Thailand in 2013. Moradi was sentenced to life for attempting to murder a police officer, while Kharzei was sentenced to 15 years for possessing explosives. Moradi, a factory technician from Tehran and a former soldier, lost parts of both legs as he tried to flee the villa on a crowded Bangkok street. He was carrying explosives from the house and dropped them in the street when police tried to stop him. The third suspect, Masoud Sedaghatzadeh, was detained in Malaysia. In 2017, a federal court there ordered his extradition to Thailand. Iranian media offered no details of the prisoners received in exchange for Ms Moore-Gilbert's release, saying only that they were “economic activists” who had been imprisoned for trying to bypass sanctions on Iran. Iran state TV footage showed them wearing Iranian flags draped over their shoulders, surgical masks and black baseball caps pulled down over their eyes as they were welcomed at the airport in Tehran by Deputy Foreign Minister Abbas Araghchi. Australian Prime Minister Scott Morrison refused to conform whether Thailand's release of the prisoners was linked to Ms Gilbert-Moore's freedom, saying he “wouldn’t go into those details, confirm them one way or the other”, but said said nothing had been done to affect the safety of Australians and no prisoners were released in Australia. Ms Moore-Gilbert thanked the Australian government and diplomats for securing her release, as well as supporters who campaigned for her freedom. A Melbourne University lecturer on Middle Eastern studies, she was detained at Tehran airport as she tried to leave the country after attending an academic conference in 2018. She was sent to Tehran’s notorious Evin prison, convicted of spying and sentenced to 10 years. She has denied the charges and maintained her innocence.