Three prisoners have escaped from a US maximum-security jail by cutting through steel bars, using service tunnels and using a makeshift rope to climb down from a roof.
"We're in a position where we absolutely need the public's help," Orange County Sheriff's Lieutenant Jeff Hallock told reporters in southern California.
"We're following every lead that we receive."
A man charged with murder is among the three escapees, who fled the prison on foot.
They were described as "very dangerous."
The search is taking place throughout southern California, Hallock said.
The escape was "clearly well thought-out and planned," Hallock said, adding that after cutting the steel bars they accessed plumbing tunnels and rappelled off a roof.
They used bedsheets to improvise the rope, Orange County Sheriff Sandra Hutchens was quoted as saying by local media.
The three inmates were identified as Jonathan Tieu, 20; Hossein Nayeri, 37; and Bac Tien Duong, 43.
Tieu is accused of murder, Nayeri of torture and kidnapping while Duong faces charges of attempted murder.
The inmates were last seen inside the jail at 5am on Friday, news reports said.
Nearly 16 hours went by before they were discovered missing.
