The Australian Prime Minister Scott Morrison has called the murder of an Israeli exchange student in Australia's southern city of Melbourne "shocking, despicable, and tragic."Police believe 21-year-old Aiia Maasarwe was assaulted then killed while walking home from a late-night comedy show.She was reportedly speaking on the phone to her younger sister when she was suddenly attacked, law-enforcement said.Maasarwe's uncle said he could not believe the killing happened in Australia.SYDNEYA 21-year-old exchange student whose body was found near a tram stop in Melbourne was on the phone with her sister when she was attacked, police say.The Australian Prime Minister Scott Morrison described the attack as "incredibly shocking." "My heart goes out to Aiia's family and friends and everyone whose life she touched. An incredibly shocking, despicable and tragic attack," Morrison Tweeted on Friday, local time. An investigation is underway.Aiia Maasarwe, an Arab-Israeli student who had been attending a university in Shanghai, was participating in an exchange program at La Trobe University in Melbourne.Police believe she was suddenly and brutally attacked just after midnight on Wednesday morning.Maasarwe had been with friends at a city comedy club before walking a short distance to catch the tram.According to Fairfax media, locals visited the scene of the attack on Thursday and Friday to offer flowers and remembrances."And remember the young student who in recent weeks had posted shots of her first sunrise of 2019, as well as Australian waterfalls and bushland," The Age newspaper wrote.Melbourne police told local media they are beginning a manhunt for "at least" one attacker, who they say may have "stalked" Maasarwe.Clothing found at the crime sceneInvestigators are examining a black baseball cap with "1986" embroidered on it and a grey t-shirt found at the scene. It was not immediately clear whether the clothing belongs to a possible suspect.Detective Inspector Andrew Stamper said he would not detail Maasarwe's injuries out of respect for her family, but there are reports police are looking into whether she was sexually assaulted before she was killed, local news outlets reported."All I will say is, this was a horrific attack. This was an absolutely horrendous, horrific attack inflicted on a completely innocent young woman who was a visitor to our city," he said, according to the Associated Press.The distressed sister "heard the sound of the phone falling to the ground, she heard some voices and that was it," Stamper said. The family alerted police around the same time that Maasarwe's body was found on Wednesday near the tram stop.Police assume the attack was random and opportunistic. One of the girl's uncles, Abed Kittani, described her as a talented student."Instead of coming home with a diploma, she is coming home in a coffin," Kittani told the national broadcaster, ABC.Join the conversation about this storyNOW WATCH: This tiny building in Wilmington, Delaware is home to 300,000 businesses Click here to read full news..