South Australian Premier Peter Malinauskas has described it as "probably the most complex and significant case" he has ever been briefed on. It involved, he said, not just the police but multiple government departments — as well as the Australian Security Intelligence Organisation (ASIO). So, what do we do know about the investigation into the 18-year-old man who now stands accused of threatening to attack the community? The teenager, who cannot be identified, was arrested on Wednesday, May 15 and charged with offences including blackmail and making repeated violent threats — including through the use of explosives and food poisons — against an Adelaide high school and public events. He appeared on Thursday in the Adelaide Magistrates Court, where his bail request was refused. What is he accused of? A police prosecutor said the man allegedly sent multiple emails to Glenunga International High School and made further threats in communication with an undercover operative. "The content of those emails [was] threatening in nature and caused alarm within the school community, prompting the school to make extra security measures," the prosecutor said. "He also said there were two futures that could happen, a 'physical attack violent future' or a 'future without a physical attack/non-violent future'." The prosecutor said the emails allegedly stated that to avoid a physical attack, the school must communicate with the sender via email. She said the alleged threats — some of which were graphic or explicit in nature, and which the ABC has chosen not to detail — were made against the school's staff and students. The prosecutor said the accused also contacted other organisations via 15 web inquiry forms which reiterated similar threats, and allegedly included threats to make "bombs that could kill or injure visitors that come to the state for events like the Fringe Festival, or the AFL Gather Round and other public spaces". She said the alleged threats also included that there was "a violent attack planned for South Australia, and Jews, and a further dislike of Glenunga International High School". The court also heard the 18-year-old had been experimenting with a homemade explosive and allegedly claimed to be conducting experiments with poison which he planned to inject into a variety of foods. The prosecutor also told the court the man was adept with computers and hacking. The man has been accused of demanding more than $20 million in Bitcoin and cash. The prosecutor told the court police had seized items from his home, and said they were investigating whether he was acting alone. She asked the magistrate to refuse bail to allow police to complete their investigation, and said officers had concerns the teen could hamper their investigation if released. How did the arrest unfold? The premier on Friday said the "technically extremely complicated" investigation involved more than 100 police, the health and education departments, and ASIO. "I met the police commissioner on the evening of May 2 and was briefed on probably the most complex and significant case I have ever received a briefing on in my capacity as either premier or previously as police minister," Mr Malinauskas said. "The arrest itself required a very substantial operation, and there were men and women who put themselves in harm's way to be able to execute that risk without fear or favour, and they deserved great credit as well." Meanwhile, SA Deputy Police Commissioner Linda Williams said that, so far, no ideology had been linked to the alleged threats. "The school community is safe," she said on Friday. "We say that we have mitigated the threat significantly. What happens now? Deputy Commissioner Williams said police security officers would continue to be present at the school. Glenunga International High sent a letter to its school community, thanking them for their cooperation and understanding. "We extend our gratitude to SAPOL for their diligent work and commitment to ensuring the safety of our students, staff, and the broader school community," the letter stated. "Their efforts have been instrumental in reaching this point. "The school will continue to operate as usual, and we remain committed to maintaining a safe and secure environment for everyone." The accused will remain in custody, and the case was adjourned until December to allow for police to finalise their investigation.