ALTAMONTE SPRINGS, Fla. — A sinkhole that forced residents to evacuate an Altamonte Springs condominium building was sparked by a crew doing testing that "led to a hole in the ground," a city spokeswoman said Thursday.

Engineers still need to determine whether the unit at the Royal Arms Condominiums at 536 Orange Drive is safe, and only then will the power be restored so that residents can return to the 16 units evacuated Tuesday night.

Michelle L. Sosa, a spokeswoman and Altamonte Springs Police senior officer, didn't specify what company was at the scene or what they were testing for, but the crew's work "led to the hole in the ground and the chain of events where we are today," she said.

Crews spent Wednesday filling in the sinkhole with dirt. Engineers hope filling it in will keep the hole from getting bigger.

"I grabbed documents, shoes, things (like) T-shirts and jeans and of courses my family pictures," said Halina Kaliciak, one of those told to leave.

Steel piles may have to be placed underneath the building along with some deeper compaction to better stabilize the ground, but that could take some time.

Experts say the area is known for sinkholes.

"There are ancient sinkholes in this area and when they did development they kind of rearranged the land and built some of these buildings on top of those paleo-features," said Byron Anderson with Structural Engineer and Inspection Inc.

A representative for the condominiums told Spectrum News 13 the insurance company could also work with the homeowners to offset some of the costs of having to find another place to stay.

Most of those evacuated are staying with family and friends and the Red Cross provided financial assistance to help 13 people find lodging at nearby hotels.