Three people, including the wife of the man found dead at Odhania village in Rajasthan's Jaisalmer, were arrested in the case, police said Sunday.
While the three were arrested on Saturday, the fourth accused was detained for interrogation on Sunday, police said.
On August 15, Khetaram was found dead in his fields and his wife had registered a murder case against some unidentified people, Lathi Station House Officer (SHO) Omprakash Chaudhary said.
During investigation, the man's wife came under suspicion and was interrogated, the SHO said.
She revealed that she was unhappy with her marriage because of domestic disputes.
The woman approached a man, Madan Meghwal, to kill her husband and promised him a sum of Rs 1 lakh and gave Rs 20,000 in advance, Mr Chaudhary added.
On the basis of the woman's statement, Madan Meghwal and his accomplice Hemaram were arrested on Saturday while Moturam Meghwal was taken into custody on Sunday morning, the officer said.
A case under Sections 302 (murder) and 364 (kidnap) of the Indian Penal Code has been registered.
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