You're getting there, but not quite there yet, since the relevant passage only reads: "The convictions were quashed four years later on the grounds that confessions to police officers had been improperly admitted in evidence."
Since you're quite close to the Strand, why don't you pop round to the Judges Library near the Bear Garden and ask for a day pass for research purposes? Tell them you're contributing to an encyclopedia article and want to get your facts straight....(kiwiexile at DMOZ)  •