2 sentences

1. 他因为当了告密者而遭到了同伴的唾弃。

   tā yīn​wèi dāng le gào​mì​zhě ér zāo​dào le tóng​bàn de tuò​qì.

   He was despised by his peers for being an informer.

   Source: Dong Chinese Dictionary

2. 这位告密者向媒体揭露了公司的财务丑闻。

   zhè wèi gào​mì​zhě xiàng méi​tǐ jiē​lù le gōng​sī de cái​wù chǒu​wén.

   The whistleblower revealed the company's financial scandal to the media.

   Source: Dong Chinese Dictionary