What do you know about a German witness?

Marcus M, he was following the Quetzal trial when he Heard to the Girls asking for help and would have been hurt. Then, he saw two guys hiding in the forest. For his security he ran away. Then, Marcus should have decided to come back later but anyone was there. He should have stated this to a forest guard in a control station. A french couple would have also heard these girls screaming during the night of april 1st.