The U.S. Coast Guard called off its search of a Chicago woman who went missing after snorkeling in a beach in Puerto Rico.

Joanna Rebis, 38, was last seen by her friends swimming off Punta Arenas in the island of Vieques on Wednesday before she failed to return.

The Coast Guard initiated a rescue mission after a U.S. Fish and Wildlife Service officer alerted the Sector San Juan around 7:17 p.m.

However, the four-day search was postponed Saturday night after conducting 22 missions that covered 2,391 nautical miles.1

The U.S. Coast Guard announced Monday it had called of the search of Joanna Rebis, a 38-year-old woman from Chicago who disappeared while snorkeling near Punta Arenas beach in Vieques, Puerto Rico, on Wednesday. 

Police report filed after Chicago native Joanna Rebis was reported missing after she failed to return after snorkeling on the shoreline of a beach in Vieques, Puerto Rico, on Wednesday

‘Unfortunately we did not find Ms. Rebis, despite the extensive search efforts from all responding agencies,’ Lieutenant Commander Alberto Martínez said in a statement Monday.

‘We remain hopeful that one day we may come to know more about the circumstances that led to her disappearance.’

San Juan resident Nico Molina took to Facebook on Sunday to seek help in the search for his friend.

He revealed that Rebis had been snorkeling by herself at the time she disappeared.

She was wearing swimming attire that included a long sleeve white t-shirt and black shorts. However, she was not wearing any fins over her feet which would have allowed her to navigate currents and waves.

‘She was lone, not wearing claps, and her GoPro camera appeared on the shore,’ Nico Molina wrote.

‘Her body has not turned up and if that is so, I think she could have drifted and floated to the southern area.’

Martínez asked visitors to use extra caution when visiting the beaches throughout the U.S. territory island and to be wary of ‘dangerous rip currents.’

‘Most of the beaches in Puerto Rico are open water beaches and do not have lifeguards, having someone looking out for you in case of a distress situation could just save your life or the life of a loved one,’ he said.