Since there has been no official news on the subject, we will build out forecast using logical and statistical approaches. The logic allows us to think that there should be the next season because of a major cliffhanger at the end of the first chapter. The original light novel consists of eleven chapters. Thus, there is enough source material for another television adaptation. Besides, the mystery series (manga and novel) is still ongoing.
As for the statistics, the data seems to be pretty favorable. On MyAnimeList, the first season of Beautiful Bones: Sakurako's Investigation has a score of 7.47/10 ~ 53,000 votes. On Hulu, the anime holds a rating of a 4.6 out of 5 stars based on ~ 650 votes. However, also worth noting that the anime has quite a relatively small target audience due to a specificity of the genre. As a result, the series creators might consider it commercially unprofitable whence such a long-term hiatus.
On the other hand, in the world of anime, it's quite a widespread phenomenon when the viewers are waiting for the update for years (and even decades). Sure, we know that you can't wait so long for the decision on renewal. But you must keep in mind that the audience of the series is quite small. Look, for instance, at the statistics of IMDb; only 132 viewers rated the series. You may now compare this indicator with the same of Attack on Titan, or at least My Hero Academia.
For you, perhaps, that just useless figures. However, any producers look at these indicators to find out a commercial feasibility of the franchise. Of course, you can argue that these statistics don't reflect the actual picture. But you should take into account that all the Japanese studios consider the US, UK, as well as European markets as a primary distribution network, right after Japan.
Summing up, it's worth noting that Beautiful Bones Season 2 still might happen. However, the odds are low. But still, thanks to the efforts of Fuji TV, a live-action drama of the same name appeared on Japanese television on April 23, 2017. Now this phenomenon may serve a major hint that the series creators are going to extend the franchise. So, Beautiful Bones: Sakurako's Investigation might return for the second season.
Sakurako-san no Ashimoto ni wa Shitai ga Umatteiru started off in October 2015 on Tokyo MX. Later TVQ, KBS, SUN, and many other Japanese networks began airing the series. Troyca Inc. served as a developer of the television adaptation. Sentai Filmworks acted as a licensor of the series in North America. Season 1 of Beautiful Bones consisted of twelve episodes. The first chapter came to an end on December 23, 2015. The anime series is available for online video streaming on Hulu, Crunchyroll, and other popular online websites.