The police arrested four criminals – $P, Q, R$ and $S.$ The criminals knew each other. They made the following statements:

• $P$ says “Q committed the crime.”
• $Q$ says “S committed the crime.”
• $R$ says “ I did not do it.”
• $S$ says “What Q said about me is false”.

Assume only one of the arrested four committed the crime and only one of the statements made above is true. Who committed the crime?

1. $P$
2. $R$
3. $S$
4. $Q$