In what Detectiv Conan Manga are Saguru Hakuba
Hakuba Saguru has been in the Detective Conan manga a total of two times.
The first instance was The Sunset Mansion (file 299-302). You might be able to read it online here, but it’s suspect and not very high quality. Your best bet will be to purchase the officially sanctioned manga however it’s available to you. In America, it’s volume 30 – here’s an Amazon link!
The second was the amazing Detective Koushien arc (file 562-566). You can read this online by visiting the Detective Conan Translation Project (http://www.dctp.ws/), clicking on “Read Vol. 54+”, then “Volume 54” in the sidebar, then navigate to “DC 54 – 9 East Detective (1)” – there are five parts in total.
The anime counterparts to these files (219, 479) are likewise excellent and are highly recommended. For further Hakuba goodness, make sure to read the Magic Kaito manga (available on DCTP) and watch the Magic Kaito anime – there aren’t that many episodes, so it’s easy to get up to speed. You can even skip to when Hakuba shows up (volume 3, chapter 2 in the manga; episode 7 – ‘The Splendid Rivals’ in the anime) if you just want the good stuff!