The world's first criminal conviction of a BitTorrent user may have opened the doors to making even downloaders of files through the technology criminally liable, an expert in computer science and law has warned. The warning came as Chan Nai-ming, who used the alias 'Big Crook', was convicted by Tuen Mun magistrate Colin Mackintosh yesterday of three charges of attempting to distribute three Hollywood films - Daredevil, Miss Congeniality and Red Planet - using BitTorrent file-sharing technology. Sentencing was adjourned to November 7 and Chan released on bail, but the magistrate did not rule out imprisonment - the offence carries a maximum four-year jail term - despite the defence lawyer's calls for a non-custodial sentence such as a community service order. Mr Mackintosh rejected defence lawyer Paul Francis' argument that Chan only 'made available' copies of the films and could not be accused of distribution. 'The defendant loaded the files into his computer, he created the .torrent files, created the images of the inlay cards and imprinted them with his logo, the statuette; he published the existence of the .torrent files, and the names of the films in question, on the newsgroup,' the magistrate said. 'He said in effect, 'Come here to get this film if you want it'. His acts were an essential part of the downloading process and ... amounted to distribution.' But Kevin Pun Kwok-hung, associate professor of computer science and law at the University of Hong Kong, pointed out that BT technology works with the downloaders also automatically becoming uploaders, and questioned the wisdom of launching criminal prosecutions against users of such technology instead of leaving it to businesses to take civil action. 'If you say by placing something on the internet, you are committing a crime, you are saying all BT downloaders are criminals because their computers are downloading and uploading,' he said. 'The key issue is whether placing something on the internet amounts to distribution, but I personally don't find the legal argument convincing - it amounts to authorisation but not distribution.' Connie Carnabuci, a partner at Freshfields Bruckhaus Deringer and head of its Asia intellectual property and information technology practice, said the ruling did not extend criminal liability to individual downloaders, but focused on 'the attempt to distribute copies of copyrighted material'. 'I think it's a fantastic ruling, especially for the copyright owners in Hong Kong,' she said. 'That an individual could go to prison may provide a policy platform for the police to educate people that this kind of activity is theft.'