Indonesian police are questioning the crew of a bulk coal carrier over an oil spill off the island of Borneo that killed four fishermen and continues to pollute local waters.
Police have taken fuel samples from the Panama-flagged MV Ever Judger, which remains in Balikpapan Bay.
The ship, which is crewed by Chinese nationals, had been due to take a load of Indonesian coal to Malaysia.
The spill continues to affect the bay, with aerial footage showing it has spread across a wide area.
The oil slick ignited on Friday morning, killing four fishermen and sending thick black smoke over the city of Balikpapan. Another man remains missing.
A police forensic team has taken fuel samples from the ship as well as from a nearby refinery operated by state-owned oil company Pertamina, East Kalimantan provincial police chief Inspector General Priyo Widyanto told ABC News.
Pertamina pipelines run across the bay.
"We're questioning some witnesses including the boat crew of MV Ever Judger, also the local residents, workers from Pertamina — and we're waiting for all the results," Inspector General Widyanto said.
Pertamina said it is not responsible for the oil leak.
It said its own testing showed the slick was diesel fuel oil, not crude oil from the refinery.
The noxious fumes from the leak continue to affect Balikpapan, which has a population of 700,000 people.
The fumes are causing health problems throughout the city, environmental group Jatam's Pradama Rupang said.
"This is dangerous for people who live around the cove," he said.
"It's also affecting the fishermen — let's say they used to be able to catch two to three kilograms of fish. Now they get nothing.
"It's a hit to the economy — all the cafes along the coast are losing their customers because of the smell."
