The two inmates charged with murder who broke out of a California jail over the weekend are back in custody, the Monterey County Sheriff's Office said Wednesday.

Santos Fonseca, 21, and Jonathan Salazar, 20, broke free from the jail after climbing through a hole they made in a bathroom ceiling of their housing unit. The inmates then squeezing through a wall before finding an escape hatch, authorities said.

According to U.S. Customs and Border Protection officials in San Diego, Fonseca and Salazar walked up to the PedWest border crossing facility at the San Ysidro Port of Entry in south San Diego County at 11:35 p.m. Tuesday. The inmates – who are both U.S. citizens – were trying to get back into the United States.

CBP officers ran the pair’s information against law enforcement databases and saw that the men were wanted.

“Officers escorted them to a secure location for further processing,” a CBP San Diego public affairs spokeswoman said.

Escaped Inmates arrested by @cbp. Thank you to our federal law enforcement partners for your team work and assistance! Press conference today at 11am at the Monterey County Sheriff’s Office https://t.co/mOMBUebRkl pic.twitter.com/fl0Q92PoI3 — Monterey Co Sheriff (@MCoSheriff) November 6, 2019

As CBP officers dug into the pair’s background, they discovered they were the men wanted by the Monterey County Sheriff’s Department on felony arrest warrants for escaping from jail.

Fonseca and Salazar were both handed over to the Monterey County Sheriff’s Department.

Monterey County Sheriff’s Department Capt. John Thornburg thanked CBP for aiding in the arrest of the escaped inmates.

Pete Flores, director of field operations for CBP in San Diego said the San Diego Field office inspects more than 200,000 travelers each day seeking entry into the U.S. at the border crossings in south San Diego.

“Due to their vigilance and thorough inspections CBP officers apprehended these dangerous individuals,” Flores said.

Courtesy Monterey County Sheriff's Department

Officials previously said the hole the inmates created at the Monterey County Jail measured about 8 inches tall and 22 inches wide in the guards' blind spot and they slipped into the walls of the jail Sunday in the city of Salinas, Thornburg said.

Inside the wall, the two inmates maneuvered past ducts and pipes in a maintenance access area until they reached a hatch. They kicked it open and made it to an outdoor area that was covered in construction fencing, rather than security fencing with barbed wire, Thornburg said.

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.

There was another escape about five years ago, when an inmate climbed through a ventilation duct in a different housing unit, he said.

Before escaping, Fonseca and Salazar had been behind bars since last year and were awaiting trial on murder counts and "numerous other felony charges" in separate cases, authorities said.

Fonseca is accused of 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 newspaper in Salinas reported.

She saw a scuffle, heard her husband screaming "no" and then gunshots rang out, Salinas police Officer Froylan Aranda testified at a preliminary hearing in March.

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 allege. 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, according to the newspaper.

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 newspaper reported. The woman was shot and treated at a hospital, while the child wasn’t hurt.

Police investigated the on Oct. 12, 2017, shooting as gang-related. Officers said at Salazar's preliminary hearing earlier this year that 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.