Complex sentence: Two were summoned to a meeting, because Mary McGlinchey was acting as an emissary the pair were lulled into thinking that there would be no danger of violence however they were led to waiting gunmen and shot dead.
Split into simpler sentences: Two were summoned to a meeting, because Mary McGlinchey was acting as an emissary the pair were lulled into thinking that there would be no danger of violence. However, they were led to waiting gunmen and shot dead.