The Tokyo Zodiac Murders

Locked room murder mystery about a amateur sleuth and his astrologue friend, who try to solve the decades old and infamous murders of an artist and his family members. 
So this was a very mixed read for me.  The murder mysteries themselves were interesting and pretty gruesome.  it was great to discover and learn about Japan in the 30s and 70s. The writing wasn't anything to write home about, though I don't know how the translation influenced that.  That being said I had problems with the pacing, too much info dumping, and the second part felt boring. The explanations given about the murders and big reveal didn't really impact me or made me gasp. I was left more baffled than anything else, like the hints didn't appear clear to me. The explanations felt like a cop out, brushed off and answered too quickly.  I didn't care for the characters, especially Kiyoshi, who came off as annoying more than eccentric. I wanted to hear more of the culprit too. 
Despite an interesting concept, the execution felt lacking for me.