New Delhi, April 25: The CBI has arrested a 25-year-old woodcutter with a criminal past in connection with the rape-and-murder of a teenaged schoolgirl in the Kotkhai area of Shimla, after his DNA sample matched the genetic material found on the body of the victim and the crime scene, officials said today.

The findings of the agency will bring relief to the families of five people arrested earlier by the state police as the CBI has not found any evidence of their involvement in the gruesome rape-and-murder in July last year, which had become a rallying point against the then Congress government in Himachal Pradesh.

The investigation which went like a crime thriller involved a team of 40 CBI officials who camped in the area around the crime scene for nine months in extreme secrecy collecting intelligence from local people, digging records of people with criminal records and following various leads which took them to Kashmir and Uttarakhand as well.

The probe, which was taken over by the agency on July 22, 2017, on the orders of the Himachal Pradesh High Court, was monitored by the top brass of the agency.

"The Director (of) CBI has been monitoring the progress of the case from day one. He expressed the satisfaction at the work done by the investigative team and forensic experts of the CFSL of the CBI for solving a sensitive and difficult case," CBI spokesperson Abhishek Dayal said here.

After ruling out involvement of five suspects arrested by the state police using call records analysis, narco-analysis, polygraph tests and corroboration of their alibi, the CBI had started the probe afresh, they said.

The agency started work on multiple fronts -- some teams worked to develop rapport with locals trying to get intelligence while others did combing operation of the forest area in concentric circles, the officials said.

The CBI officials spoke to over 1,000 people to get inputs and recorded statements of over 400 of them, they said.

Meanwhile, some teams started collecting a DNA trail of people, history sheeters and families living in the area to do profiling by CFSL experts who used advance tests such as percentage match and lineage match.

These techniques help to ascertain the clan and the area to which the suspect belongs, they said. The agency had collected 250 such samples of people from a wide range of backgrounds. In one case, the agency found that some percentage of a sample matched with the DNA of blood samples found on a liquor bottle at the crime scene and clothes and the body of the victim, the officials said.

During questioning, it surfaced that a relative of the person whose blood sample was taken had worked at a nearby locality when the crime had taken place.

Following that trail, the agency reached the suspect's house in Kangra district where it found that he had a criminal past and had been on the run since September, 2016 after getting bail in an attempted murder case, they said.

After DNA profiling of parents, the CFSL team concluded that samples found at the crime scene were of their son.

But the case was far from over as the suspect was untraceable and did not keep contact with his family and remained without any mobile to prevent digital tracking.

The agency short-listed some of 80 people who had high probability of being contacted by the suspect and started trailing them.

In remaining cases, the agency started monitoring phones but the suspect used phones of strangers to make calls.

The CBI teams interviewed the people whose phones were used to make these calls, made a track of location from where they were made, and pattern in which he was moving, to come up with a profile of the suspect with the help of experts of the CFSL.

After one such call made around April 13 was intercepted by the agency, the teams were rushed to a farm in Roharu area near Shimla. The team spotted one labourer in the farm whose profile matched with the one they were trailing.

He was immediately nabbed and brought to Delhi where tests confirmed his involvement in the crime as DNA matched hundred per cent with the blood sample collected from the site.

During the questioning, it emerged that the teenaged girl was in a school in Mehsu village from where children used to walk for about five kilometers, which took over one-and-a-half hours, to their Balsang village located on a hilly terrain.

The villages are sparsely populated separated with a thick Halaila forests which children crossed while returning from their school. On July 4, Anil Kumar who was allegedly in hiding and working in a nearby farm, was passing through that area when he spotted the minor girl who was returning from school after completing her sports meet there.

He overpowered her and allegedly raped and murdered her, the agency alleged. The Class X student had gone missing on July 4 and her naked body was recovered from Haliala forests in Kotkhai on July 6.

The accused was produced before a court in Shimla today and was sent to judicial custody.

In connection with its probe into the case, the CBI also arrested then Inspector General of Police (IGP) Z H Zaidi, then Deputy Superintendent of Police (DSP) Manoj Joshi and six other policemen for the custodial death of one of the accused arrested earlier by the state police.

Zaidi was heading a Special Investigation Team (SIT) which was initially probing the rape-and-murder case.