A boy who spent more than 12 hours underground after falling into a sewer pipe in Griffith Park described making the marks that helped crews find him early Monday.

Jesse Hernandez, 13, fell about 25 feet into a 4-foot diameter pipe while playing on top of a Los Angeles Bureau of Sanitation structure in Griffith Park at around 4:30 p.m. Easter Sunday.

“When I was sliding down, I was making those marks because I knew they were going to come in and try to find me,” Hernandez told KTLA at his Huntington Park home, where he was recovering.

Hernandez said he didn’t see the wooden plank that covered what firefighters described as a drainage ditch.

“I just stepped on it and I fell through it,” the teenager said.

Rescuers searched for Hernandez for more than 12 hours, eventually discovering him about a mile east where he was reported missing.

They found him “alive and talking” as they opened a maintenance hatch near where the 134 Freeway goes under the 5 Freeway to place camera, L.A. Fire Department Captain Erik Scott said at a news conference early Monday.

“One of the cameras showed fingerprints on the sides of the sewer, some elbow scrapings. Right away, they thought something’s close by,” said Adel Hagekhalil, assistant director at L.A. Sanitation.

Hernandez was going to undergo “decontamination,” the Fire Department said. He was taken to the County USC Medical Center and later released.

Hernandez’s stepfather, Arturo Ramirez, called the rescue a miracle.

“We were praying,” Ramirez said. “I was very, very happy. All we wanted to do was hug him and kiss him.”

Ramirez told KTLA that Hernandez’s blood test had been cleared, but the family would continue to monitor his condition at home.