“It is now three weeks that we have no news about our parents,” begins the haunting message tweeted Friday by the children of Vittorio Missoni, Maurizia Castiglioni, Elda Scalvenzi, and Guido Foresti. The foursome, along with a pilot and copilot, disappeared without a trace shortly after their twin-engine tourist plane left the Venezuelan island of Los Roques en route to Caracas the morning of Jan. 4. “It has not been clarified what happened to the flight from Los Roques to Caracas,” the children write. “To date the only certainty we have are the geographical coordinates where the aircraft vanished from the radars.”

Missoni and his companion and two Italian friends had just finished a fishing vacation on the Caribbean island and were headed back to the mainland to catch a flight back to Italy. Their plane disappeared from radar roughly 11 miles from the island airport, and despite a massive air and sea search, not one speck of debris has been found. Using the radar data and trajectory estimates, Venezuelan authorities have pinpointed exactly where the plane would have hit the water, according to officials in Venezuela, but nothing has been discovered. Deep-sea submarines have been deployed to assist in the underwater search.

Immediately after the disappearance, Vittorio Missoni’s sister, Angela, told reporters in Italy that she felt her brother had not perished in an airplane accident, but had been kidnapped. Vittorio’s son Ottavio later echoed that theory in an extensive interview with an Italian newspaper. “A plane cannot vanish in this way, on a short route, without leaving any trace,” he told the paper. “I remain convinced that the least plausible reason is that they crashed into the water.”

Reports that dozens of planes and passengers had been kidnapped in recent years in the same area, coupled with a mysterious cellphone message sent from Foresti’s phone to his son’s phone a day after the plane disappeared, further fueled theories that the plane might have been diverted and had not gone down at all. Now it seems the whole family is even more convinced that someone might know something more about the disappearance. Posted with the hashtags #findvittoriomissoni and #findthem, the tweet, signed by the seven children of the four passengers, pleads that any information could be “pivotal” to the investigation. “Each and every day, we keep on asking ourselves if there might still be other useful information to aid the investigations. Whoever that day was on site, whether on land, on ocean or flying, might have noticed something and thought it was of no interest, but that could be relevant for us and for the investigations. Every single detail is essential.”

Anyone with information is asked to send an email to troviamoli@gmail.com, an account created to handle tips about the disappearance.