CCTV, released by police, shows the deeply distressing last few moments 25-year-old Inna Petrova has with her tiny child, clutching her tightly, before she hands her over.
The unemployed painter at one point can be seen turning her back on Natalia Zhdanova who has flown 1,970 miles from St Petersburg to Omsk collect the baby.
But then Inna kisses her little one for the last time and hands over the child, who is cocooned in a bright pink wrap.
Natalia then used a faked birth certificate - which listed the baby as hers - to show airport security before flying back to her home city with the child, police say.
Inna who later said she was “hysterical” at giving away her child is seen wiping tears from her eyes on the video, released by the Investigative Committee, which probes serious crimes in Russia.
She now admits she was wrong and says she wishes she could wind back the clock.
Ahead of the child's birth, Natalia had sent Inna a payment of 3,000 roubles - just £34.
Natalia, a 43-year-old teacher, is said to have empty nest syndrome after her adult son left home, and wanted one last baby.
She is already bringing up another adopted daughter.
Now both women have been formally detained as a criminal probe is launched under Russia’s child trafficking laws.
They could each face up to ten years in jail.