Terms for subject Idiomatic containing in the night of

English	Russian
in the dead of night	посреди ночи (markovka)
in the dead of night	под покровом ночи (Someone was sneaking around in the dead of night. Wakeful dormouse)
in the middle of the night	глухой ночью (глубокой ночью Alex_Odeychuk)
in the middle of the night	глубокой ночью (Tanya Gesse)