I may be mis recalling, but I thought the main point of the I, Robot series was that regardless the law, incomplete information can still end up getting someone killed.
In all the cases of killing, the robots were innocent. It was either a human that tricked the robot or didn't tell the robot what they were doing.
For example, a lady killed her husband by asking a robot to detach his arm and give it to here. Once she got it, she beat the husband to death and the robot didn't have the capability to stop her (since it gave her it's arm). That caused the robot to effectively self-destruct.
Giskard, I believe, was the only one that killed people. He ultimately ended up self-destructing as a result (the fate of robots that violate the laws).