Please help me to find this Yaoi Manga/Manhwa

The MC was in the police station convicting for the serial killings and sexual molestation of a number of young boys in the 1970's I guess. MC met the uke at the church hostel. friendship was forbidden at the church hostel, friendships were suspicious because everything had a possible sexual link.
There was a scene where a spoiled teacher made MC suck his cock violently,

MC who felt notorious after the phases he had gone through being sexually harassed at church convinced the uke to leave the church and run away with him. Next they were walking by the railway lines, MC thought to Push uke under the train and he'll die, then he won't be able to defend himself, then he could strip him naked and have sex. MC pushed the Uke in front of the train when it came in close proximity, but somehow he managed to fall off on the other side, uke gave a shocked face toward MC, I didn't do it on purpose i was slipped MC said to uke.. what MC tried to do earlier uke didn't talk about it and calmed down, uke said "ugh... We'll die at this rate if we continued walking to the station following railway lines" ! MC discovered a tunnel and his sexual thoughts returned giving off a big smirk on his face and then the first chapter ended with it.

Next I remember there was some boy roped up naked and was unconscious. there were candles set around him. MC untied and put his dick inside him and started thrusting, and said I wonder if you should be fully developed or not (something like that). After that he buried that boy in the tunnel.
And then it's back in the police station, (adult) MC was convicting the phases he occurred on those boys he used as sexual object. I remember where MC said "I was looking for the normal but they had to be 8 and more than 14" The prosecutor got frustrated to hear that saying "What did you do with them f*#cking psycho" ??

I hope it helps!! it was still on going and the art style wasn't great, on top of that it was an underrated manga/manhwa.