Naya Rivera Missing: The Tragic History of Lake Piru, Where 'Glee' Star Disappeared

Seven people drowned in the lake between 1994 and 2000

In September 2000, the Los Angeles Times published a report on the dangers of the lake, following the death of Eric Cruz. The 25-year-old Van Nuys resident drowned just 10 feet from shore. Witnesses said he was an inexperienced swimmer and pushed his boogie board away. Douglas West, Lake Piru's parks and recreation services manager in 2000, said there were about 12 drownings during his 23 years working at the lake. He said most drownings involve a swimmer who is inexperienced and not wearing a life jacket. They often overestimate their swimming abilities and go into prohibited areas.

"The only thing I can emphasize is that if swimmers are around water, they need to wear a personal flotation device whether they know how to swim or not," West told the Times in 2000. "That will save their lives."

The area is 'notorious for the winds'

Ventura County Sheriff Sgt. Kevin Donoghue explained to PEOPLE that searching for Rivera is like trying to find a needle in a haystack. "Water searches are really difficult," he explained, adding that it could be "several days" before they find clues or recover Rivera. He said Lake Piru's tough conditions make the search more difficult. The area is "notorious for the winds," Donoghue said.

Rivera was last seen when she rented a boat Wednesday afternoon. After she did not return the boat in three hours, the staff at the concessions stand began a search. The boat was found with Josey sleeping aboard and wearing a life jacket. An adult-sized life jacket was found on the boat, a possible sign that Rivera was not wearing hers. "If she had a life jacket, we would find her floating, clearly she is not," Donoghue told PEOPLE.

A man drowned after the wind blew him away from a boat just five minutes after swimming

In May 2010, 36-year-old Roberto Barrios drowned in the lake. He was celebrating his nursing school graduation with about two dozen people when he took a swim with two other people. The three people were swimming for about five minutes when the wind blew them away from the boat after just five minutes of swimming. Witnesses rescued two of them but were unable to find Barrios, who disappeared under the water, according to the Ventura County Star. Barrios disappeared on a Saturday but his body was not recovered until two days later.

In 2008, a father drowned after trying to save his 5-year-old daughter

On Aug. 25, 2008, Anatoly Smolyansky dived into the Lake Piru water to save his 5-year-old daughter after she fell overboard. While his daughter was saved by her 9-year-old brother, Smolyansky never resurfaced. Divers from various departments in Southern California spent over 600 hours in the waters searching for him. His body was not recovered until Sept. 1, 2008, the Ventura County Sheriff's Office said.

An employee went missing for 17 hours in February 1998 before he was found in the water

In February 1998, lake employee Arthur Raymond Caldera was found dead 17 hours after he went missing, the Los Angeles Times reported at the time. A co-worker saw the bait shop was unlocked and called sheriff's deputies after Caldera did not arrive at work on time. Deputies said Caldera may have slipped into the water the evening before he was found and drowned.

More than 20,000 people have signed a petition for more signs at Lake Piru warning about the dangers

After Rivera went missing, Change.org user Erin Jordan launched a petition calling for new signs to warn visitors of the dangers of Lake Piru. "Lake Piru is a very deep lake with very bad whirlpools, people have been asking for years for the city to put up warning signs for swimmers," Jordan wrote. "Locals of Ventura County don't go to Lake Piru for this reason!" She noted that tourists do not know "what they're getting into" and added that "need justice for all those who got lost at Lake Piru." More than 20,000 people have already signed the petition.