(CNN) FBI toxicology tests have determined that the deaths of three American tourists in the Dominican Republic were due to natural causes, a US State Department official said Friday.

The findings are consistent with those presented by Dominican authorities.

The FBI assisted with the toxicology tests of three of at least nine Americans who died there in recent months. The spate of deaths has left vacationers to wonder if they should cancel their trips to the Caribbean tourist destination.

The bureau assisted in the investigations of the deaths last Spring of Nathaniel Holmes, Cynthia Day and Miranda Schaup-Werner.

Schaup-Werner, a 41-year-old Pennsylvania resident, died in May at the Grand Bahia Principe in La Romana, as did the 63-year-old Holmes, and the 49-year-old Day, a couple from Maryland.

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