SAN FRANCISCO — Two murder suspects who escaped from a jail on California's central coast eluded an intense manhunt, traveled hundreds of miles and crossed into Mexico but were arrested trying to walk back into the United States, authorities said Wednesday.

Jonathan Salazar, 20, and Santos Fonseca, 21, were arrested by U.S. Customs and Border Protection officials at a port of entry in San Ysidro — the nation's largest border crossing — early Wednesday, said Monterey County Sheriff's Office Capt. John Thornburg.

Thornburg said the two are in the custody of Monterey County officials and are on their way to a jail in Salinas.

Jonathan Salazar and Santos Samuel Fonseca. Monterey County Sheriff's Office

Salazar and Fonseca escaped Sunday from the Monterey County jail in Salinas after climbing through a hole they made in the ceiling of a bathroom, squeezing through a hollow wall and kicking open a hatch.

Investigators have not yet determined how long they worked on making the hole or if anyone else helped them escape the jail in the farming city of about 160,000 people roughly 100 miles south of San Francisco. They were reported missing at 8:15 a.m. Sunday.

Thornburg said authorities received a tip that the pair, both born and raised in Salinas, had been spotted in the Mexican border city of Tijuana, around 400 miles south of Salinas, and alerted federal officials.

How the pair made it to Mexico, why they decided to return to the United States and what documents they used at the port of entry is under investigation, he said.

"The good news here is they are in custody again," Thornburg said.

Salazar and Fonseca will be housed separately in a different housing unit from the one they escaped, Thornburg said, adding that officials had already made security improvements to the jail. He said he couldn't provide details.

Before being spotted in Tijuana, investigators received a credible tip from an employee at a motel in Marina about 10 miles from the jail who told authorities Salazar had checked in there Tuesday morning, but authorities found no one in the room after a nearly eight-hour standoff, Thornburg said.

"It all looked like we had Mr. Salazar in a motel," he said. "Unfortunately, last night he wasn't there."

Both had been in custody since 2018 and were awaiting trial on murder counts and "numerous other felony charges" in separate cases.

Salazar was arrested in the shooting death of 20-year-old Jaime Martinez as the victim drove in Salinas with his girlfriend and 18-month-old son. The woman was shot and treated at a hospital, while the child wasn't hurt.

Police investigated the Oct. 12, 2017, shooting as gang-related. Officers said his tattoos, including the letter P on his cheek, refer to his Sureño offshoot gang, La Posada Trece, the Californian reported. His trial was scheduled to begin in January.

Fonseca is charged with shooting Lorenzo Gomez Acosta, 37, to death on June 2, 2018, while the victim sat in his car on a video call with his wife in Mexico, the Californian reported.

She saw a scuffle, heard her husband screaming "no" and then gunshots rang out, Salinas police Officer Froylan Aranda said.

Fonseca told police that his gang leader told him to kill someone to prove he was still loyal to the "Boronda gang," Detective Gabriela Contreras testified. Acosta was reportedly chosen at random.

Three days later, Fonseca shot and killed Ernesto Garcia Cruz, 27, in a Salinas park, authorities said. He told police that the gang leader also ordered the slaying and that he picked his girlfriend's ex-boyfriend "to send him a message," Contreras said.