Nadezhda Kulikova was convinced the exorcism would help her child's "behavioural problems" in Moscow, Russia.
A mum left her six-year-old son tied to a tree in a forest all night with a sack taped over his head in an attempted exorcism, police say.
Nadezhda Kulikova, 33, is accused of suspected attempted murder with "particular violence" after the shocking incident.
Police in Moscow, Russia, were today granted a further 48 hours to investigate Kulikova, who it is said dumped her son Lev in a remote woodland on Sunday evening to "cure his behavioural problems".
A close friend said Kulikova has been talking to a priest recently about exorcisms.
It is believed the youngster had tried to drown the family dog in Moscow when Kulikova allegedly snapped.
She is said to have tied Lev to a tree, put a sack over his head and hands and left him in subzero temperatures for around 13 hours.
When the child escaped, a shocked driver spotted him beside a busy nearby road and alerted authorities.
It came a day after the mother driven him on a 100-mile round trip to see a priest called Father German noted for exorcisms.
They attended a "mass cleansing".
Kulikova's close friend said the priest runs "a special session the the exorcism of demons".
The source added: "To treat him, Nadya (Nadezhda) even asked for the help of shamans from Siberia.
"And in November I flew with them to the Philippines - we were looking for a specialist who could help."
But Kulikova has denied trying to kill her child.
She reported him missing eight hours after allegedly tying him to the tree.
The driver who found Lev said: "I put him in the car and we chatted about what happened.
"He said that he was rude to her [Kulikova].
"[He said:] 'I wanted to drown the doggy, but mum caught me and wanted me to drown.
"The doggy is loved more than me."
Lev is now in care in Moscow.
Kulikova remains in detention as police continuing to investigate the incident.