Sleuth (noun)

1. A detective, especially a private detective.
2. A person who is skilled at investigating and discovering facts and information.

Origin:

From middle english sluȝe, from old english slǣwþ, from proto-germanic *slaiwaz ("track, trail"), from proto-indo-european *slóywos ("track, trail").

Examples:

1. The sleuth was hired to investigate the theft.
2. The sleuth followed the trail of the criminal.
3. The sleuth uncovered the truth behind the murder.
4. The sleuth was able to solve the case.
5. The sleuth was able to find the missing person.