Police have arrested a doctor in western India for allegedly injecting six people with a lethal overdose and burying most of the bodies at his farmhouse, an officer said Tuesday.

Santosh Pol, dubbed "Doctor Death" by local media, was arrested in a town in Maharashtra state last week during a police investigation into the disappearance of one of his victims.

"Pol has confessed to killing around six people including five women and one man. We have recovered four bodies from his farmhouse and one from (outside) his (town) residence," police inspector Padmakar Ghanvat told AFP.

"He has been constantly changing his statements during interrogations, which makes it difficult for us to understand his motives," Ghanvat said.

All of the alleged victims went missing in the picturesque town of Wai, 230 kilometres (143 miles) south of Mumbai, in recent years. But little is known of their connection to the doctor.

Television footage showed police leading Pol around his farm, while other officers operated mechanical diggers as curious villagers watched.

Police have also taken Pol's nurse into custody on suspicion of helping him carry out some of the killings, officers have been quoted by local media as saying.

Pol allegedly killed his latest victim with a lethal overdose of an unknown drug after she threatened to expose his previous murders, according to the reports.

Last year police arrested an Indian doctor accused of trying to set a patient's body on fire after he died during treatment.

Earlier this month Indian police arrested the head of an upmarket hospital in Mumbai and four doctors on suspicion of organ trafficking.