The Naked Sun by Isaac Asimov
A second robot / mystery novel.
Solaria is a planet known for making robots. Its humans live isolated lives, avoiding contact with other people. A murder victim dealt with other humans via holographic image only, never being in the same room as other people. Still, somehow someone beat him to death. Odder yet, one of his robots stood around and did nothing. Although the victim had contact with robots, the Laws Of Robotics should make it impossible for any of the robots to harm any human. Other Solarians are also adverse to being in the same room as others, making it unlikely one of them could have been the killer. The most likely other suspect is his wife who was on their property but never saw him in person. (On Solaria, spouses are assigned and couples don't procreate by sex.)
No murder weapon is found. The robot that was the only witness can't say what happened. The Laws Of Robotics make seeing a human harmed traumatic to a robot.
Earth detective Elijah Baley is reunited with R. Daneel Olivaw [a robot] to investigate. The idea of calling in an Earther is shocking and suggestive of the problems of the case. And speaking of shocking, the detective has the disgusting idea of interviewing people face to face. The story includes good twists.
The book is good, but not as fresh as it would have been when published 50 years ago.