“We are feeling helpless, powerless and want to help in any way.”

Heather Morris is embarking on a rescue mission for her Glee co-star Naya Rivera.

Last week (8 July), Rivera – who played Santana Lopez on the beloved musical comedy series – went missing after renting a pontoon boat on Lake Piru with her four-year-old son, Josey.

When the rental boat wasn’t returned at its 4pm expected time, employees operating the rental stand went out to look for the actress, but found her son alone in the boat with his lifejacket on.

According to TMZ, Josey told investigators that his mother jumped in the water without her lifejacket and didn’t return to the surface. The Ventura County Sheriff’s Department scoured the area until dark, but no trace of her was found. She is now presumed to be dead.

Morris, who played Rivera’s on-screen love interest Brittany Pierce, tweeted authorities on Sunday that she wants to “conduct a foot search and rescue mission along with a small group of friends” at Lake Piru.

“I understand your team is doing EVERYTHING in their power, but we are feeling helpless, powerless and want to help in any way,” she wrote. “I have left a message with the department of Rescue and Air today, and I will call again tomorrow. Thank you.”

Over the weekend, the Ventura County Sheriff’s Department warned fans of Rivera to not conduct searches on their own, tweeting: “1. The lake is closed. 2. Temps are already in the 90’s. 3. The terrain around the lake is very steep and rugged. Our teams are well equipped and highly trained. We don’t want to have to rescue you.”

Their social media account also announced that the cabins on the banks of the lake would be searched after social media theorised that Rivera might have ended up in one. However, Sgt. Shannon King told People that the cabins are “not occupied” and “nothing came of it”.

 “There’s no evidence to say she left the water,” he explained. “It appears to be 100 percent just a tragic drowning.”