Krishna's sleazy stories about relations between slain teenager Aarushi Talwar and her family's domestic help Hemraj, which were corroborated by none, attracted the suspicion of the Central Bureau of Investigation (CBI) sleuths and eventually helped the agency to nail him as one of the murderers.
"We first got suspicious about Krishna as he was the one who talked about relations between Aarushi and Hemraj. All stories were given by Krishna and were not corroborated," said CBI's Joint Director Arun Kumar, who is leading the CBI investigations.
The CBI investigators sensed foul play. A further probe revealed that Krishna, 32, the compounder of dentist Rajesh Talwar, had "consciously derailed" the probe.
"It is apparent that he led the investigators on a different track," Kumar said on Friday.
Krishna was the only one to told Noida Police that the teenager and the 42-year-old servant, Hemraj, were into a relationship.
Based on this theory, the Noida Police arrested Talwar May 23, saying he killed his only daughter Aarushi and servant Hemraj as he found them in an "objectionable but not compromising" position on the night of May 15.
Aarushi, 14, was found killed in her room in her Jalvayu Vihar residence in suburban Noida May 16. The Noida police initially named Hemraj as the main accused but backtracked after his body was found on the terrace a day later.
"We suspected Krishna after Rajesh Talwar said during his interrogation that two days before the murder he had badly scolded Krishna in public. Other witnesses, like Talwars' driver, confirmed that Krishna was agitated after that," Kumar said.
The crime scene depicted that there was a friendly entry into Talwars' residence on the night of the incident.
"The crime scene depicted that there was no forcible entry into the house. The scientific evidence suggested a friendly entry," said Kumar.
Krishna's involvement in the twin murders got confirmed after it was found that he had Hemraj's mobile.
"After Aarushi's murder came to light on May 16, Krishna dialled from Hemraj's number. At that time the cell was present in the Jalvayu Vihar area itself. Krishna lived nearby," Kumar said.
"During his interrogation Krishna said that Hemraj had given his mobile to him before being killed. However, during his narco-analysis he said that he unintentionally took Hemraj's mobile with him," Kumar said.
The CBI team, which included forensic experts, also put Krishna through several scientific tests. His psychoanalysis tests presented him as an "aggressive, manipulative and evasive person who is not loyal to anybody".
"We conducted two lie-detector tests on him and there were deceptions on all major issues. We then subjected him to a narco analysis test with court orders. During the tests he confessed to the crime and gave details about it," Kumar added.
He was arrested June 13.
During his narco test, Krishna named Raj Kumar, the servant of the Talwars' family friends Anita and Praful Durrani, as well as the domestic help of a neighbour, Vijay Mandal.
The two were arrested later.
According to the CBI, Krishna with Raj Kumar and Vijay Mandal killed Aarushi and Hemraj after trying to sexually abuse the teenager.