The families of three young American women found dead at a Belize beach resort said they are “deeply alarmed” by new reports suggesting carbon monoxide levels were high — and are demanding answers about the “suspicious” deaths.

The three women from Massachusetts who were on vacation in Belize died of carbon monoxide poisoning, officials confirmed Wednesday.

The Belize National Forensics Science Service executive director, Gian Cho, said Thursday that carbon monoxide poisoning killed three American women found dead while at a vacation resort there in February.