A preliminary investigation shows "murky and cloudy" water in a public swimming pool helped conceal the body of a drowned Haitian woman for two days while people swam there, authorities said.

The Bristol County district attorney's office said the body of Marie Joseph was submerged at the bottom of the 3.6-metre deep end of the pool, in Fall River, Massachusetts, from Sunday afternoon until Tuesday night.

Marie Joseph holds family friend Dalianys Melendez in the public swimming pool in Fall River, Massachusetts. Ms Joseph's body was later found in the pool two days after she drowned. Credit:AP

Joseph, 36, was a hotel housekeeper in Newport, Rhode Island. She was from Haiti and had five children. Her body was discovered after it floated to the surface shortly before some youngsters sneaked into the pool for a clandestine swim on Tuesday night.

The medical examiner's office has determined the manner of her death to be accidental and the cause to be asphyxiation by drowning.