IG (Kanpur Zone) Ashutosh Pandey said that police yesterday recovered diary from her in-laws' house and are going through it.
Jyoti's husband Piyush Shyam Dasani was arrested with police claiming that he had confessed to have got Jyoti killed with the help of his driver as he was having relations with another woman.
The driver, his two accomplices and Piyush's paramour have also been arrested.
Pandey said, "Surprising evidence have come to light since the seizure of the diary and this would strengthen the case against the accused in court."
According to police sources, she wrote in the diary that "he doesn't leave an opportunity to mentally torture me. He never asks me about what I wish for. My family life has been ruined. He is always busy with his female friends."
Pandey also said that police have received the details of SMSes exchanged between Piyush and his alleged lover in the last three months. These are also being studied.
The top police official, however, said that they still could not get hold off the weapon used in the crime.
Meanwhile, a social media campaign has been launched by Jyoti's supporters seeking justice in the case.
A Facebook community page "Justice for Jyoti" created yesterday.
Earlier, Dasani in his complaint lodged with the police after the incident had alleged that he and Jyoti were returning home from a restaurant on July 27 night when some motorcycle-borne youths tried to overtake their car.
A scuffle broke out between him and the youths after one of the bikes hit the car, according to the complaint.
Dasani had claimed that he was beaten up by one of the youths after which they abducted Jyoti and also took the car along with them.
Two days ago, DCP Rakesh Naik, who was probing the case, was taken off ground duty after he hugged Piyush and planted a kiss on his forehead in a police station.