Professor parents of the 29-year-old youth arrested for attacking former Haryana DGP SPS Rathore today said their son was under treatment for depression for the last six months and he was dead against any kind of injustice.

"But no one is allowed to take law in his hands," the assailant's father Sushil Kumar Sharma, a professor of Mechanical Engineering in IT-Banaras Hindu University (BHU), told PTI.

Sharma said, "I would try my best so that my son gets relief on health grounds... with all his medical reports, I will approach the police and authorities at Chandigarh."

"For the last six months, Utsav (Sharma) is under treatment for depression... abnormal circumstances must have forced him to do so (attack Rathore)."

"Utsav used to say he could not tolerate injustice and talked on such matters," he said.

Utsav's mother, who is a psychiatrist and a professor at the Institute of Medical Sciences, BHU, also confirmed that her son was not medically fit.

Abnormal circumstances must have forced Utsav to stab Rathore, but it was not expected of him, she said adding at the same time that the act could not be justified.

Utsav is pursuing a post-graduate diploma course in animation and film design at the prestigious National Institute of Design (NID), Ahmedabad.

Rathore, convicted of molesting budding tennis player Ruchika Girhotra, was stabbed with a pocket knife by Utsav outside a court in Chandigarh. Utsav was immediately arrested by security personnel.