"We traced those spreading hoaxes to Majene. We already have their identities. We hope to arrest them soon," police chief spokesman Insp. Gen. Setyo Wasisto said here on Tuesday.
Setyo said one of the hoaxes warned the local people that the Bili Bili dam has cracks and was feared to break and collapse soon.
The Mamuju Gowa police had to go checking and found out the news was merely hoax. The water reservoir is in good condition and safe.
Another false information said that a bigger quake with a magnitude of 8.1 on the Richter scale would follow in Central Sulawesi, that the National Agency Handling Disasters (BNPB) has to counter the hoax.
There were also photos of dead bodies said to be the victims of Palu disaster, but it was also hoax as the photos were those of dead victims in Middle East war.
Setyo said the information about blockades and plundering at airport was also a hoax as the photo showed the people queuing to board an aircraft.
Meanwhile, the Communications and Informatics Ministry (Kominfo) said it had found false information or hoax related to the earthquake and tsunami in Donggala and Palu and surrounding areas such as the death of Palu Mayor.
Information about free flight from Makassar to Palu was also a hoax as the Hercules aircraft of the Air Force flying to Palu from Makassar was carrying logistic aid, paramedics, medicines, food and heavy equipment.
Kominfo appealed against the spreading of hoaxes and called on the people not to believe information other than that from official sources.
President Joko Widodo has expressed anger at the spreading hoax passing strict order to police to arrest anyone found spreading false information confusing the people.
Reporting by Dyah Dwi Astuti
Editing by Albert Saragih