Madden found that Maclean had unfairly imprisoned 91 local people, some for as long as four years, on dubious grounds and without even the formality of a trial; and he also reported that Maclean illegally claimed that he had the authority to inflict capital punishment. Madden's enquiries, and subsequent parliamentary select committee, also concluded that Maclean lacked formal powers to act effectively against the trade, and the Colonial Office stepped in.
Madden's investigation revealed that Maclean had wrongly imprisoned 91 local residents for extended periods on flimsy grounds and without due process; he also exposed Maclean's false claims of authority to impose capital punishment. Madden's findings, supported by a parliamentary committee, led to the Colonial Office stepping in to address the trade issue.