source: [GJ部の皇紫音たちが探偵の真似をしているGIF画像｜無料GIF画像検索 GIFMAGAZINE 489587]

sniff around

informal investigate covertly, especially to find out confidential or incriminating information about someone.

sniff (a)round: ｟くだけて｠ (情報･秘密などを求めて)かぎまわる.

sniff around someone

to try to get (someone) as a romantic partner, employee, etc.

｟主に英･くだけて｠ 〈人･組織などが〉〈恋人･客･従業員など〉を手に入れる.

e.g. His engagement hasn't stopped him from sniffing around other girls.

e.g. Rival companies have been sniffing around her for years.