A wave of earth and debris crashed through the small town of Casamicciola Terme amid heavy rains on Saturday, destroying houses and sweeping cars down to the sea.
The latest body to be recovered was a 15-year-old boy, who was reportedly killed along with his younger brother and sister. Their parents were among those still missing.
The other victims included a 21-day-old baby.
As the island mourned its dead, it emerged on Monday that the former mayor had tried to raise the alarm four days earlier and had asked for at-risk areas to be evacuated.
He sent 23 registered PEC emails to authorities, but “nobody answered me,” former mayor Giuseppe Conte (a namesake of the former prime minister) told the Corriere della Sera newspaper.
Geologist Aniello Di Iorio told the Corriere della Sera daily there were “high risks” of further landslides on parts of Ischia, an island near Capri that is thronged with tourists in summer.
Experts said the disaster was caused by a fatal mix of deforestation, overdevelopment, and a lack of mitigation strategies.
National Council of Architects head Francesco Miceli said it was “a tragedy foretold”.
“This is not an isolated case, the risk areas are numerous and affect many regions of our country,” he said.
Italy needs to “quickly define more incisive territorial control strategies (and) concrete intervention programmes, and disburse adequate resources”, he said.
The disaster has also raised questions about the number of buildings constructed in areas that are at a high risk of flooding and landslides, often without permits.
On Sunday, the Italian government declared a state of emergency on the island and approved an initial allocation of two million euros in funding to address the aftermath of the landslide.
Officials had said they expected to evacuate and find temporary homes for between 150 and 200 people.
Local authorities called on residents of Ischia to stay inside to avoid hindering the rescue operation.
Ischia’s schools will remain closed on Tuesday.
The peninsula, off Naples, is no stranger to states of emergency following earthquakes, volcanic eruptions or severe weather.
Casamicciola Terme, a spa resort of 8,000 inhabitants in winter on the lush island of Ischia, near Capri, was hit by an earthquake in 2017 that killed two people.
It was completely destroyed by a much more powerful earthquake at the end of the 19th century.