There is only one reason or motive for these cops to lie on their own reports.
Come on.
No, there are many reasons why a report may contain a falsehood. It could be a deliberate mistruth or a sincerely held misconception. The motivation could be to get away with a crime or simply make the truth easier on the deceased's family. Although as I explained earlier, I don't think there is sufficient evidence to conclude that Officer Tensing misrepresented anything in his report.