on (someone's) tail

Translations
на хвосте у (кого-то)
The police were on the suspect's tail for hours before they finally caught him.
Полиция была на хвосте у подозреваемого несколько часов, прежде чем они наконец поймали его.
Definitions
Following closely behind someone, often in a competitive or pursuing manner.
Words
tail

noun
хвост