Priyanka alleged that she was raped and criticised the UP administration for delaying the probe into the incident.
On September 16, the body of 17-year-old Class 11 student was found hanging from the ceiling of her hostel room.
"The reason why UP is at the top in crime against women can be gauged from the fact that the body was found in the hostel on September 16. The girl's family kept pleading with the administration to bring out the truth, but nothing happened," Priyanka, also the party's eastern UP in-charge said in a series of tweets, attaching a news report.
"The student was raped. This is the fourth such incident in front of us. Shameful," she tweeted.
The Congress leader had earlier written to Adityanath seeking an inquiry into the alleged suicide and asserted that action is of utmost importance for the safety of girls in the state.
Priyanka in her November 28 letter said the incident was "heart wrenching" and assumed importance in the context of the security of girls studying in various institutions in the state.
Senior Congress leader Jitin Prasada last week visited the deceased's family and expressed solidarity with them. He also called for an urgent inquiry.
According to the UP Police, a suicide note found in her room stated that she was taking the extreme step as her roommates had publicly humiliated and taunted her over the theft of some snacks.
However, her father had lodged an FIR against school principal Sushma Sagar, hostel warden, and two students alleging murder.
( With inputs from IANS )