The cause of death for the Laguna Niguel man who died last week after snorkeling in Goff Cove is under investigation, according to the coroner's office.

The autopsy has been completed on Robert Mirett and results should be available in 10 to 12 weeks, officials said.

According to police, witnesses reported that the 60-year-old man entered the water alone around 1:30 p.m. with snorkeling gear on.

At around 4 p.m. Mirett was seen floating in the water, still in snorkeling gear. Citizens rushed to bring him to shore and an off-duty paramedic administered CPR.

Police were called around 4 p.m. and Mirett was pronounced dead when emergency crews arrived.

joanna.clay@latimes.com

Twitter: @Joannaclay