Search continues for presumed drowned Glee star Naya Rivera

Sheriff's department patrol boat searches for body of Naya Rivera.
Naya Rivera has not yet been located. Photo credit: Reuters.

The search for the body of missing Glee star Naya Rivera is continuing at the California lake where she is presumed to have drowned two days ago

The 33-year-old actor went missing on Wednesday (local time) after her four-year-old son was found alone in a boat she had rented on Lake Piru, Southern California.

Rivera is presumed dead and local authorities searching the lake have yet to find any sign of her. 

"Multiple teams of professional search and rescue personnel are actively searching Lake Piru for clues to the location of Naya Rivera. With over 80 people involved in the search right now, we are using helicopters, boats, ATV vehicles, and ground personnel to try and locate her," the Ventura County sheriff's department tweeted.

Divers assisting the search are struggling with visibility due to murky water and debris on the floor of the lake.

In response to these difficulties, the Ventura County sheriff's department is employing advanced sonar equipment in the search efforts which use sound waves to detect objects underwater.

The department's captain Eric Buschow said the equipment picked up an object on Thursday evening that seemed "promising". However, on Friday morning the search team used a remotely operated underwater vehicle to examine the object and Rivera was not located.

Buschow said the search is focused on the north and east sides of the lake as this is where the boat was found.

The sheriff's department has also released CCTV footage of Rivera and her son at the Lake Piru dock. The footage shows the pair strolling along the dock before boarding the boat Rivera rented and heading north across the lake. 

Authorities announced on Thursday that the search and rescue operation had moved to a search and recovery mission. 

Buschow said the sheriff's department is putting as many assets and personnel into the search as they can.