Do you think Mr. S is a reliable source? Explain your reasoning.

No, I don't perceive Mr. S to be a reliable source. It is because the way he describes that how he discovered the Hae's body is enough to raise thr brows of viewers and listeners.

Explanation:

In Episode 3 of Serial, Mr. S is called by detectives to investigate his side of the story and how he came to find Hae's body which was found completely camouflaged in the dirt.

Mr. S can not be considered a reliabel source by the way he describes the event of his founding Hae's body in the forest, 127 miles away from the main road. Mr. S gives description to the detectives that he got off his car to pee and had a bottle of beer in his hand. It is interesting to note and enough to raise brows of listeners and viewers of the episode that how was he able to see Hae's body which was covered with dirt and was behind a heavy fallen log, which made impossible for someone to see the body easily (especially if someone is drunk).

So, because of this reasoning, one can not considered Mr. S to be a reliabel source.