The U.S. Coast Guard is still searching for a family who is thought to have gone missing in a sailboat about 60 miles from Monterey Bay in California after transmitting distress signals this past weekend.

The Coast Guard received the distress message at around 4:20 p.m. Sunday afternoon. The caller said the ship was taking on water.

About an hour after the first message, the radio operator onboard said the ship was sinking and that the whole family was abandoning her: "Coast Guard, Coast Guard, we are abandoning ship. This is the Charmblow, we are abandoning ship." They also said they had fashioned a raft made of water coolers and life vests.

The boat did not have a working GPS system and officials are still unsure of the identities of the people aboard, according to the Monterey Herald.

In the radio messages, the Coast Guard was only able to determine that the four included a man, his wife, their four-year-old son and his cousin.

"There is still no information on where the boat was coming from, where it was going, or who the people on board are," said Coast Guard Chief Petty Officer Mike Lutz.

The agency said it hopes that someone will be able to identify the voice from the distress call.

The Coast Guard has posted audio of the crew's final message on their website.

The search has included ships, helicopters, and airplanes, but rough seas this past weekend and water temperatures between 40-50 degrees make chances of long-term survival unlikely.

The Coast Guard frequently responds to distress calls from stranded, disabled, or sinking ships off U.S. coasts, but they have also been the victims of prank calls, particularly recently. In May and June of 2012 the Coast Guard responded to calls in Texas and New Jersey that involved sinking ships that turned out to be non-existant. The search effort in New Jersey cost as much as $85,000.

CNN asked the Coast Guard if this could be a similar hoax given that no one has come forward. A Coast Guard spokesman said that all reports are treated as legitimate unless evidence proves otherwise.

UPDATE: The Coast Guard has suspended its search and rescue mission citing a possible hoax, according to CNN.

The U.S. Coast Guard is suspending its search off the California coast for a distressed 29-foot sailboat that was carrying a couple and two children, and said Tuesday the incident is "possibly a hoax."

The mission's cost has reached several hundreds of thousands of dollars since Sunday, said Cmdr. Don Montoro.

Searchers have been scouring the water off San Francisco for the people distress calls said were on the boat. That included the couple, their four-year-old child, and the child's cousin, who the Coast Guard said was younger than eight.

Coast Guard investigators will look into the incident and "prosecute it and investigate it to the best of their ability," Montoro said. "We're not investigating it directly as a hoax, but we are pursuing every avenue. It's certainly a possibility."

The penalty for making a false distress call is up to 10 years in jail and a $250,000 fine.