"I have already told you (я вам уже говорил) that your reports reached me rapidly (что ваши отчеты быстро доставлялись мне), being forwarded instantly from Baker Street to Coombe Tracey (будучи незамедлительно пересылаемы с Бейкер-стрит в Кум-Трэйси). They were of great service to me (они очень мне пригодились; to be of service — быть полезным), and especially that one incidentally truthful piece of biography of Stapleton's (и особенно та, случайно /рассказанная вам/ Стэплтоном, правдивая часть из его биографии). I was able to establish the identity of the man and the woman (я смог установить идентичность = личность мужчины и женщины), and knew at last exactly how I stood (и знал наконец точно, с кем имею дело: «в какой ситуации нахожусь»; to stand — стоять; занимать определенную позицию). The case had been considerably complicated (дело значительно осложнялось) through the incident of the escaped convict (эпизодом со сбежавшим каторжником) and the relations between him and the Barrymores (и отношениями между ним и Бэрриморами). This also you cleared up in a very effective way (это вы тоже прояснили очень действенным способом), though I had already come to the same conclusions (хотя я уже пришел к тем же выводам) from my own observations (/исходя/ из моих собственных наблюдений).
rapidly ['r&pIdlI], incident ['InsId(@)nt], observation [,Obz@:'veIS(@)n]
"I have already told you that your reports reached me rapidly, being forwarded instantly from Baker Street to Coombe Tracey. They were of great service to me, and especially that one incidentally truthful piece of biography of Stapleton's. I was able to establish the identity of the man and the woman, and knew at last exactly how I stood. The case had been considerably complicated through the incident of the escaped convict and the relations between him and the Barrymores. This also you cleared up in a very effective way, though I had already come to the same conclusions from my own observations.