A series of mysterious deaths of Americans vacationing abroad are causing alarm at home.
In the latest episode, a Pennsylvania woman died inside her Dominican Republic hotel room just days before a Maryland couple was found dead at the same resort, U.S. officials confirmed.
Miranda Schaup-Werner, 41, a psychotherapist from Allentown, died shortly after her arrival at the Grand Bahía Príncipe hotel in La Romana on May 25.
Schaup-Werner was celebrating her ninth anniversary with her husband, Dr. Daniel Werner. She was having a drink from the minibar in her room when she was struck with "acute physical distress" and collapsed, Jay McDonald, Werner's brother-in-law and a spokesman for the family, said in a statement to NBC News.
Werner performed CPR on his wife as he waited for the medics to arrive. She was later pronounced dead.
Just five days later, Nathaniel Holmes, 63, and Cynthia Day, 49, were found dead in their room at the same resort. Doctors said they died from fluid in their lungs.
"I was numb,'' Day's sister, Sonya Jackson, said on TODAY Wednesday. "I'm still numb."
The U.S. State Department did not identify an exact cause of Schaup-Werner's death.
However, McDonald said in his statement that the official cause of death was respiratory failure and pulmonary edema, or fluid in the lungs. He also said he felt the three cases were connected.
"After learning of the startling similarity to the incident with the Maryland couple just days later at the same resort, family became alarmed about possible implications, and contacted the U.S. State Department to express serious concerns over Mrs. Schaup-Werner's mysterious death, the disturbing similarity, and to ask for investigation,'' McDonald said.
McDonald added that no toxicology report was done as part of the cause of death inquiry, and her glass and drink were not tested.
He has asked for privacy while the family mourns her loss.
"At this point, we are not aware of any connection between these incidents,'' the State Department told NBC News in a statement. "We are monitoring this closely and will provide updates as appropriate. We stand ready to provide assistance as requested."
The deaths of the three tourists come on the heels of two other frightening incidents, including one in the Dominican Republic.
Delaware woman Tammy Lawrence-Daley alleged she was badly beaten in January while staying at the Majestic Elegance Punta Cana, on the eastern tip of the island. In late May, a Texas couple, who were parents of a 2-year-old boy, died of mysterious illness while on vacation in Fiji.