There are two past tenses in Turkish. One of them is görülen geçmiş zaman (seen or direct past tense) and the other one is duyulan geçmiş zaman (heard, indirect, reported or inferential past tense). Their names may vary according to different sources. But the main point is that the first one is used for events that you have witnesssed, you have seen when the action was taking place, and the other one is used for actions that you haven't witnessed, you have heard from somebody else. Görülen means seen and duyulan means heard.
Seen past tense is used for actions that the subject has witnessed, it is used for actions when the subject have seen the action taking place. For example, let's say you saw a car accident while walking in the street. When you tell people this event, you should use seen past tense, and when people whom you told this event tell this event to other people, they should use learnt past tense as they didn't witness the action taking place but they heard from you.