The 23-year-old habitual offender, Rahul Raj, who was on Friday convicted for the rape and murder of an engineering student, has been awarded death sentence.

Special CBI Judge AK Mishra had on Friday found Raj guilty of the rape and murder of the victim, who was a fourth-semester engineering student in a college located in the Ormanjhi area of Ranchi.

The case

The naked body of the victim was found in the morning of December 16, 2016 in her house in the Booty Basti area, where she lived alone, officials said. Her sister had called one of her neighbours to enquire about her well-being as she was not answering her phone, they added.

When the female neighbour went to check on her, she found her body amidst smoke as bedding etc. in the house were on fire, the officials said.

An autopsy confirmed that the victim was raped and strangulated to death, they said. The Jharkhand police had collected DNA samples from the body of the victim. The case triggered huge student protests in Ranchi. Joined by students of other engineering colleges and locals, the protests identified the victim as "Ranchi's Nirbhaya".

The CBI took over the investigation after nearly 15 months in a case that was almost a blind one, the officials said. The state government had recommended a CBI probe on January 3, 2017, but it reached the agency only after the Centre issued a notification on January 25, 2018, after over a year.

The CBI registered the case on March 28, 2018 and launched the hunt for the culprit with the profiling of the people in the area, classifying them into various age groups, and previous cases to narrow down on 10 suspects.

Raj figured in the list of suspects as he used to live in the locality and was absconding after the body was discovered, the officials said.

It emerged during the probe that he was arrested in Patna for an alleged sexual attack on a minor and was in judicial custody for over three years after he had jumped the bail, they added.

The CBI came to know that he had 10 cases against him in Uttar Pradesh and Bihar, the officials said. After fleeing, Raj had allegedly used a number of aliases to evade arrest, they said.

The agency collected the blood samples of his parents from Nalanda, where they lived, which showed a perfect match with the only male DNA sample collected from the body of the victim, the officials said.

The CBI started looking for Raj when it came to the agency's knowledge that he was in the custody of Lucknow police, where he had five cases of different nature against him at the Hasanganj police station, they said.

He was taken into the CBI's custody on June 23 this year from Lucknow and brought to Ranchi, where his blood samples were collected, which matched the DNA samples collected from the victim's body.

Armed with conclusive forensic evidence, the CBI filed a chargesheet against Raj within three months and the charges were framed on October 25, the officials said.

The trial started on November 8 and during the day-to-day hearing, the agency examined 30 prosecution witnesses over a period of 16 days. The process was completed in a little over a month with the conviction of Raj by the special court on Friday, the officials said.

(With PTI inputs)