Patna, Aug. 25: Driven by the wish to lead a lavish life and smitten by illicit romance, schoolteacher Sibu K.K. murdered his employer and proprietor of a renowned public school in the Patna City area six years ago. The wife of the victim and another teacher of the institution were also involved in the heinous crime.

Sibu and Mercy, the wife of the victim, had developed an illicit relationship. After Thomas suspected them, the duo decided to eliminate him to grab his wealth and get married. They took another teacher of the school, Dipankar, into confidence to eliminate Thomas, who was found dead near Faridpur village on the outskirts of Patna City on November 16, 2005.

Sibu and Mercy were arrested from Madhya Pradesh on August 20 and produced before a court in the state capital on Wednesday. Dipankar was arrested today from Haziganj locality under Chowk police station.

The investigating officer of the case, Kamla Pati Singh, said: “All the three prime accused have been arrested.”

During interrogation Sibu told the police that he had developed an illicit relationship with Mercy, who hailed from his native village. “Thomas had suspicion about our relation and he often used to misbehave with his wife, almost half his age,” Sibu said, adding that he and Mercy hatched a conspiracy to eliminate Thomas, who had earned huge money from the school.

“Mercy and I decided to get married after the death of Thomas. But that was not possible without the help of Dipankar, a local guy,” he said.

“After getting the nod from Dipankar the plot to murder Thomas, who was scheduled to return from his native place in Kerala on November 15, 2005, was hatched,” Sibu said.

Sibu and Dipankar went to Patna Junction to receive Thomas. “He was taken to Deedarganj in Dipankar’s van and strangulated to death. His body was later dumped in a roadside ditch,” he told the interrogators.

Sibu and Mercy lived in Patna City for some time to keep a tab on the police action. “When we thought everything was going on the expected line, we decided to leave Patna City and settle somewhere else,” Sibu said.

After reaching Kerala, they got married. Later, the couple shifted to Madhya Pradesh and joined a school at Barwani.

The police had closed the Thomas murder file in absence of evidence in 2007. But social activist Sammi Kapoor submitted a petition to the state human rights commission demanding action against the erring cops. Subsequently, the panel assigned central range deputy inspector-general (DIG) Jitendra Kumar to conduct a through investigation into the case. The DIG probed the case and submitted a detailed report to the director-general of police in February 2010. A copy of the DIG’s report was also submitted to the commission, which issued directives to take action against the accused.