Police reinforcements took up position today near the island where isolated tribal hunters killed an American man, though no effort was to be made to recover his body, officials said.
Hampered by restrictions on going to North Sentinel and the hostility of the Sentinelese people, authorities are counting on the expertise of anthropologists and tribal welfare specialists to access the remains of 26-year-old John Allen Chau.
Mr Chau was killed by arrows fired by the Sentinelese hunter-gatherers last week after he illegally went ashore in an apparent attempt to convert the tribe to Christianity.
The police have used a helicopter and a ship to get close to the protected island but failed to spot Mr Chau's body or identify the place where he was killed.
"To make the picture better and clearer another police team is being sent to the North Sentinel island waters," Dependra Pathak, Andamans chief of police, told AFP.
Seven people, including six fishermen, have been arrested for leading Mr Chau to North Sentinel.
The police hope the fishermen can give more clues to the place where he was slain.
"Police have obtained seven days custody for three of the accused," Mr Pathak said.
"They will be interrogated on various aspects of the case including the sequence of events, the sea route followed for the island, the location where the victim landed, the place of incidence and location where Chau was last seen," he added.
Foreigners and Indians are banned from going within five kilometres of the island, to protect the Sentinelese, believed to number about 150, from outside disease.
While a murder case has been registered, experts have discounted any possibility of action against the tribe for the death.
Authorities say Mr Chau paid the fishermen to take him as close to the island as possible and then took his own kayak to North Sentinel.
"It will also be ascertained whether the victim had taken the help of these fishermen or others to venture to the island on an earlier occasion," the police chief said.
Mr Pathak said the police will also take a new look at Mr Chau's personal journal, in which he expressed fears that he might be killed.
He said he told the tribe after arriving: "My name is John. I love you and Jesus loves you...Here is some fish!"
Fishermen saw the tribe burying his body on the beach the following day, another missionary wrote in an email to the dead man's mother, according to the Washington Post.
Recovering the body could take days, if it happens at all, as authorities insist they cannot disturb the tribe or their habitat in the highly sensitive zone.
The few photos that exist of the Sentinelese show them all but naked carrying spears, bows and arrows.
The tribe reportedly killed two fishermen whose boat drifted onto the island in 2006. They also fired arrows at a helicopter checking for damage after the devastating 2004 Indian Ocean tsunami.