The Brothers Karamazov
Pyotr Ilyich Perkhotin
Perkhotin is a young town official and a friend of Dmitri's. He lends Dmitri some money in exchange for Dmitri's pistols as collateral. A few days later Dmitri returns, seemingly swimming in cash, covered in blood, and prepared to redeem his pistols. It's only after Dmitri leaves for Mokroye that Perkhotin becomes deeply suspicious of his behavior. After asking around, he alerts the authorities. By the end of the novel, Perkhotin is also involved in a flirtation with Madame Khokhlakov.