For the convenience of discussion, I will summarize some of the important points in this file until full translation comes out. I cannot provide any detailed translation of the dialogues for now. Also note that this is derived from the Chinese translation, not the Raw, so expect some minor errors.
Page 1 ~ 8 (Crime scene)
After finding Akiyama's phone, they saw a mail sent at 5:32 PM. The content is: "I've found the first victim Takeda's phone inside a certain person's belongings. I'm now sending this mail to you from that phone. Since this person is a police officer, you need to find an excuse and come to that small hut in Saijosan [Note: the mountain's name]. I'll explain in details there. - Yamato Kansuke"
Kansuke seems to have turned off his phone so he's out contact.
Conan suggests that the mail might not have been sent by Kansuke because it wasn't his own phone, and he wouldn't be stupid enough to leave an incriminating evidence there. Kuroda counters this (after making suspicious comments as spoilered earlier) by saying that he probably didn't have enough time to get rid of it. He also shows that the victim had Kansuke's number black-listed, possibly in order to prevent him from finding the phone.
On the rope that was used to hang Kano, Kansuke's fingerprints were found on both the upper part AND the part surrounding the victim's neck, which Koumei said hadn't been touched by anyone until the forensics arrived. Kuroda orders Kansuke's arrest as the prime suspect for the serial murder.
Kuroda tells them to retreat to the police station because Kansuke wouldn't stay around the mountain area after they came. Akiyama's body was left there for the moment because it's dark and the ground's muddy after the rain.
Kuroda tells Saegusa to return in his car because there won't be enough room inside Koumei's due to the wheel at the backseat, while grinning suspiciously.
Page 9 ~ 14 (Inside Koumei's car)
Koumei reveals that there has been a similar hanging case in the past. The parents of the bank robbery suspect [mentioned in the backstory] committed suicide by hanging themselves. After Kansuke arrived at the scene, he said that they could possibly still be saved, climbed up a chair and untied the rope. However, unlike the current case, the rope was tied to the roof beam instead.
The rope hanging Kano was tied with two loops [see image], Kansuke held the upper loop to put the body down [see 915 images].
Conan asks the positions of everyone after that. [see 915 images for clearer views]
Conan asks if there was anything that could distract everyone's attentions, Koumei tells him about the message. [see 915]
There are similarities between the police officers' names and the names of the generals that died during the fourth battle of Kawanakajima: Takeda Shigeru = Takeda Nobushige; Kano Shouji = Hajikano Tadatsugu; Akyama Shinsuke (former surname Aburakawa) = Aburakawa Nobuyoshi; Saegusa Mamoru = Saegusa Morinao; Yamato Kansuke = Yamamoto Kansuke. So Saegusa Mamoru and Kansuke are most likely the remaining targets.
Koumei tells the story about the bank robbery: The suspect was about to surrender, however, Takeda's group acted rashly, which enraged the suspect and he began shooting. Takeda had no choice but to kill him. Yamato was mad at this and asked Takeda if he thought that it was alright for him to kill the suspect since he was a police officer.
Apparently the suspect's phone had been lost. Before he was killed, he was speaking with someone on the phone: "If I'm caught then you will be done too. The origin of the gun and X will be exposed..."
On Yui's phone, Kano was saved on Ta-gyou. This is because his original surname was Tsuchiya (土屋), but was changed after his marriage. He's currently living separately with his wife.
Page 15 ~ 16 (Police station)
Kansuke's still out of contact, but this time his phone is busy instead.
Saegusa reports that someone has spotted a person resembling Kansuke, and is going to confirm that, but doesn't have a car. Kuroda orders Koumei to lend his car to him.
Kansuke sends Koumei a message: "The events of the past are like a current." [This is a literal translation, it seems to be a poetry of some kind.]