Notice how there are very few takes; Hitchcock rearranged the set during shots to shoot the film with very few edits.
25: At the party, the women talk of marriage. Phillip is asked how he cut his hand. They ask about David (the deceased). David's father (Sir Cedric Hardwicke) talks with Janet about David. Phillip is told he's a moon child and that his hands will bring him great fame. (he just choked David to death with his hands). The birth of something new.
-45: (the movie is 1:25 long): Talk of a man's honor. Rupert (James Stewart) jokes about how murder would improve society. He jokes murder should be an art and the privilege of those who commit murder should be reserved for those few who are really superior individuals. Rupert mentions cut a throat week and strangulation day (David was strangled). Cedric asks Rupert to stop, it's too morbid and asks who would decide who was superior and who was inferior. Rupert stops joking but Brandon Shaw (who planned and assisted in David's murder) believes that superior people are above moral concepts. Cedric says that line of reasoning reveals a contempt for humanity. Discovery.
45: Rupert hears from Mrs. Wilson that there was an arguement earlier and that the chest where David's body is hiding isn't normally used for serving food. Rupert asks Phillip what is going on - Rupert senses tension. There's a siren and we see a large cloud of smoke in the distance. Phillip is unraveling and mentions the book Crime and Punishment. Now that I'm aware.
60 and -25: Brandon and Phillip remove books from the chest and open it to view David's body. Someone rings. It's Rupert, he said he forgot something. Intense turbulence as Phillip cracks and Brandon urges him to hold together. Moments later Rupert arrives and eventually he learns the truth. The end of the movie occurs as we hear the police siren - we know they will arrive soon and arrest Phillip and Brandon for murder. There's no going back now and The final turning point.