MOCOA, Colombia - The number of people killed in southern Colombia's massive mudslides climbed to 290 on Wednesday, as officials investigated how the horrific disaster might have been prevented.

In addition to the dead, 332 people were injured in landslides that buried the town of Mocoa after flooding caused by days of torrential rains.

The mudslides occurred on Friday after heavy rains caused three rivers to overflow, strewing earth, rocks and tree debris over the area.

Mocoa was home to 70,000 people, about 45,000 of whom were affected by the disaster, according to the Red Cross.

Hardest-hit by the tragedy are impoverished neighborhoods populated with residents uprooted Colombia's five-decade-long civil war.

Authorities have opened an investigation to determine what sort of "preventive and corrective action" ought to have been taken to prevent the disaster, prosecutors said.

Meanwhile, looting has become a problem in some areas.

Local officials urged the government to dispatch more police and troops to secure the region and prevent the looting of abandoned homes.

"What the mudslides didn't carry away, the thieves did," one survivor of the disaster, Juan Luis Hernandez, 33, said in the devastated San Miguel neighborhood of Mocoa.

Meanwhile, government agencies, land use experts, and environmental organizations had said for years that Mocoa could face dangerous flooding. Many who lived in the most vulnerable areas were aware of the warnings, even if they didn't heed them. And yet the city continued to spread into the floodplains west of downtown.

"Unfortunately, in Colombia we don't have a good assessment of risk, or good land use policies to prohibit people from settling in areas like these," said Marcela Quintero, a researcher with the International Center for Tropical Agriculture, one of the organizations that raised the alarm about deforestation in the area.

Mocoa was vulnerable because of its location, amid a confluence of rivers in the wet subtropical Amazon region of southern Colombia. The danger had grown worse as trees were cut down for cattle ranching and other agriculture, removing critical protection against flooding and landslides.