By CBS3 Staff

PHILADELPHIA (CBS) — An investigation into the mysterious deaths of three American tourists in the Bahamas is underway in Philadelphia. Samples taken from the bodies and the nearby villas where they were staying in the Bahamas are now at a lab in Philly.

The toxicology results are expected back in a week.

Two couples in their 60s, from Tennessee and Florida, got sick at a Sandals Resort on Exuma.

One couple died. Another man also died and his wife remains in serious condition.