US mainstream news outlets like CBS News with actual reporters on the ground at the time: https://www.cbsnews.com/news/there-was-no-tiananmen-square-massacre/
Classified US communications with assets on the ground: https://wikileaks.org/plusd/cables/89BEIJING18828_a.html
Image Analysis
From your CNN link:
Saying that the “Tiananmen Square massacre” killings actually happened in other parts of the city may be an important academic distinction, but it isn’t a particularly stirring defense of the army’s actions.