"Jagriti Sigh, 35, the second wife of Dhananjay Singh, has been getting medical treatment from a psychiatrist in Delhi for several years," a police officer told IANS.
"Dhananjay had also filed divorce papers in a district court here in June this year on the ground of his wife's mental condition," said the officer.
Jagriti was arrested for torturing her maid Rakhi, 35, to death and torturing another servant Rampal, 17, while Dhananjay, who represents Jaunpur in Uttar Pradesh, was nabbed for destroying evidence and violating the provisions of the Juvenile Justice Act.
During interrogation, police came to know that the maid was employed at the MP's house for nine months while the boy servant was working for an year.
According to the complaint given to the police, Rampal said he and the other maids did everything in the house from cleaning of clothes to taking care of a child. Rampal said he would get money from his mother but never got any salary from the employer.
On April 1, Jagriti's guest Renu came for lunch. She asked Rakhi to cook "besan chilla", and when this was not done by the time she returned, she beat Rakhi with a broom and then cut her hair with a blade.
"She used to give us deadline for work. And when we missed that, she used to beat us," said Rampal.
Rampal said Jagriti installed CCTV cameras in the bedroom and bathroom as well.
He also said that Dhananjay ignored their complaints whenever they told about the beatings. He even beat them himself on two occasions.
Police said considering the gravity of the case, they have sought permission of the government that a panel of doctors conduct the post-mortem examination of the maid.
Meanwhile, police Wednesday traced another maid Meena, 48, who worked in the MP's household.
Meena was taken to a relative of Dhananjay in Delhi after Rakhi's death. She was told not to say anything about the brutality, said the officer and added that burn injuries were found on Meena's waist. She was admitted to the Ram Manohar Lohia Hospital.
The police had received a call from the MP's flat number 175, South Avenue in New Delhi area Monday night, informing them about Rakhi's death, who died early morning.