Widow Says Husband Died Under Mysterious Circumstances in Dominican Republic

His death was ruled a heart attack, but now she wonders if it was something more.

For Dawn McCoy, a dream vacation became a nightmare when her husband suddenly became ill and died last year.

It was last July, and they were staying at the Hard Rock Hotel in the Dominican Republic. McCoy said her husband David Harrison's death was ruled a heart attack by authorities in the Dominican Republic, but in the wake of the recent spate of mysterious deaths at two sister resorts in the country, she now wonders whether something else could be to blame.

"We were having a great time ... and we ended up coming home as a broken family," McCoy told Inside Edition. "My husband's story needs to be told ... something's not right in the Dominican Republic."

She added that her husband was in excellent health at the time. 

"My husband was a very fit, very healthy person when he passed away," McCoy said.

Three deaths at two sister resorts in the span of five days have sparked calls for answers from the victims' family members. 

Miranda Schaup-Werner, 41, and her husband, Dan Werner, checked in to the Luxury Bahia Principe Bouganville on May 25 to celebrate their ninth wedding anniversary, but by the end of the day, Schaup-Werner was dead, and officials determined the cause of death was a heart attack.

That same day, Edward Nathaniel Holmes, 63, and Cynthia Ann Day, 49, checked in to the Grand Bahia Principe La Romana hotel, which is next door to the Luxury Bahia Principe Bouganville. They were later found dead on May 30.

A Colorado couple told Inside Edition they became seriously ill at the Grand Bahia Principe hotel last summer as well. 

Kaylynn Knull said she and her boyfriend enjoyed their vacation until they noticed their room beginning to smell of chemicals. They said they suffered from dizziness, blurred vision, stomach cramps and shortness of breath. 

"We both woke up soaked in sweat at 4 a.m.," Knull said. 'We were kind of terrified. We booked a flight home before the sun came up."

They were sick for six weeks. A doctor in the U.S. told them they had been poisoned by a pesticide and they're now suing the hotel. 

The U.S. Centers for Disease Control and Prevention is investigating the complaint of the couple who suspect they were poisoned. 

The FBI is now involved, working with local authorities in the Dominican Republic to try to determine what caused the recent deaths of the tourists.