Answer:
Letters, diaries, speeches, and photographs are examples of primary sources. Artifacts such as tools are also primary sources.
Explanation:
Other tools that historians use are secondary sources. They are written after a historical event by people who did not see the event.
I believe that eyewitness are not a reliable source to solve a crime or problem. Those eyewitness play a major role in the investigation meaning that they have a advantage to change minds. Some studies think that people over the age of 50 years old aren't reliable for testimony. Though, some might think that study accusation is absurd, it may be correct in some ways.
Hope I could help! :)
Is this a physics question or history answer?