FALL RIVER, Mass. – A preliminary investigation shows that “murky and cloudy” water in a public swimming pool helped conceal the body of a drowned woman for two days while people swam there, authorities said Friday.

The Bristol County district attorney’s office said the body of Marie Joseph was submerged at the bottom of the 12-foot-deep end of the pool from Sunday afternoon until Tuesday evening.

Joseph, 36, was a hotel housekeeper in Newport, R.I., and the mother of five.

Her body was discovered when it floated to the surface shortly before some youngsters sneaked into the pool for a clandestine swim Tuesday night.

The state Medical Examiner’s Office has determined the manner of her death to be accidental and the cause to be asphyxiation by drowning.

The probe shows the water in the Fall River pool was murky from the time the pool opened for the season last Saturday. Visibility tests conducted Wednesday revealed a diver couldn’t be seen at a depth of 3½ to 4 feet below the surface of the water.

“Although this office is releasing this preliminary information regarding the case today, the investigation into the death, the circumstances surrounding it and the delay in discovering the body is ongoing,” the district attorney’s office said.

The Department of Conservation and Recreation, which runs Veterans Memorial Pool, immediately closed all 30 of its deepwater swimming pools and began reviewing safety and operational procedures.

Commissioner Edward Lambert said that 11 pools were set to reopen Friday after safety inspectors found they met all safety guidelines. Other pools will reopen once their reviews are complete.

But the Fall River pool will not reopen anytime soon because its entire staff has been suspended. City officials also have said that they will not permit it to reopen until the state assures them that swimmers will be safe there.