But the phone calls were a cruel hoax. Their daughters were in fact alive, and safe. One mother was told by staff at her daughter's childcare centre that her two-year-old little girl was sleeping soundly, while the mother who rushed to school stood in disbelief as teachers brought her daughter to her. Only later did it emerge that the women were victims of a grim prank, perpetrated by a man who posed as a police sergeant and a State Emergency Service worker. Phillip Zillner chose his victims at random, having found them on Facebook, Melbourne's County Court heard on Wednesday. Over six months, Phillip Zillner made the terrifying phone calls to mothers. Credit:Facebook

Between September 2016 and March 2017, he made three terrifying phone calls. No clear reason was given in court for why the 37-year-old man scared the mothers, other than he has significant mental-health problems, including Tourette Syndrome and autism, and a socialisation disorder. He also felt hostility towards people who rejected him or had what he lacked, the court heard. Zillner followed his daytime phone calls by ringing two of the women at home in the evening and making sexually explicit remarks, which he repeated to their husbands.

Also in late 2016, Zillner stalked a woman he had dated by telling her she would be tracked and that he would be in her home when she wasn't. He also showed up at her workplace and yelled at her. Despite the phone calls about the children being lies, Zillner's offending caused prolonged psychological damage on his victims. One of the mothers was later diagnosed with post traumatic stress disorder and depression, another is plagued by sleep problems and panic attacks and the third fears receiving another similar phone call. The mothers and the woman Zillner dated are all less trusting of others, the court heard. Judge Michael McInerney described Zillner's offending as outrageous.

"It is grievous indeed. Heinous is another word. Bizarre is another word," he said. But the judge found while Zillner understood what he was doing, a psychiatric assessment determined the former labourer's disabilities had a major impact on his offending. The mental-health problems meant sentencing had to be moderated, the judge said. Zillner has spent 440 days in custody and must serve another 90 in jail. After that he will serve a two-year community corrections order, to include mental-health treatment. He pleaded guilty to three counts of recklessly causing injury, three of stalking, two of using a carriage service to harass and impersonating police. He has prior convictions for stalking and making transmissions that interfere with aircraft communications.

Judge McInerney told Zillner he would be dealt with more harshly if he reoffended. Zillner said he understood. "I have got a better and positive life to look forward to," he said before he was escorted back into custody.