Jǐng / fāng / shōu / dào / le / yì / fēng / nì / míng / xìn / xìn / zhōng / tí / gōng / le / zhòng / yào / xiàn / suǒ。

警方收到了一封匿名信，信中提供了重要线索。

The police received an anonymous letter containing important clues.