MIAMI BEACH, Fla. — The Coast Guard said Thursday that it had found four additional bodies in its search for dozens of migrants lost at sea off Florida but would suspend its rescue operations at sunset if it doesn’t receive any new information.

Homeland Security Investigations officials said they were actively investigating the case as a human smuggling operation.

Authorities have now found a total of five bodies, leaving 34 missing five days after the vessel capsized on the way to Florida from Bimini, a chain of islands in the Bahamas about 55 miles east of Miami.

The Miami office of Homeland Security Investigations has launched an inquiry, saying the migrants’ journey was most certainly part of a human smuggling operation. Under federal law, a smuggler convicted of causing a death is eligible for execution.

The lone survivor was found hanging onto the 25-foot vessel about 40 miles off Fort Pierce, Fla.