- The shooting incident happened on Monday.
- According to the Riverside County Sheriff's Department, six people were declared dead at the scene, while the seventh person died in hospital.
- The police department said evidence located at the scene suggests that the deceased were allegedly involved in an illicit marijuana growing operation.
Seven people were fatally shot at what authorities called an illegal marijuana growing operation in the southern California countryside and suspects were being sought on Tuesday.
The Riverside County Sheriff's Department responded to a report of an assault with a deadly weapon on Monday at 12:33.
Deputies found a woman suffering from gunshot wounds at a home in the unincorporated area of Aguanga, 100 miles (161 km) southeast of Los Angeles. Paramedics rushed her to the hospital, the sheriff's department said in a statement.
Six others with gunshot wounds were also found at the residence in the 45 000 block of Highway 371, the statement said.
"All six victims at the location died as a result of their injuries. Despite life-saving efforts by medical personnel, the female who was transported also died from her injuries," the statement said. "In total, seven victims died as a result of this incident."
More than 1 000 pounds (453.6 kg) of marijuana and several hundred marijuana plants were found at the scene, the sheriff's department said.
"Evidence located at the scene indicated the location was being used to manufacture and harvest an illicit marijuana operation," the statement said.
While cannabis remains classified as an illegal narcotic under federal law, California in 2018 legalised its commercial distribution. As the most populous US state, California opened the largest legalised, regulated and taxed marijuana market in the country.
A search of the area failed to immediately locate suspects. An investigation was underway and no further information was immediately available, sheriff's department Corporal Lionel Murphy told Reuters.
"This appears to be an isolated incident and there is no threat to the general public," the sheriff's department said.