Officer Sylvester Young ­­was working the Sunday night shift at the youth detention center run by the District when two teens picked the locks on their rooms, grabbed him from behind and beat him. The attack was swift, he said, and he quickly blacked out.

When Young came to, swollen, bruised and dazed, he was locked in Room 10 and couldn’t get out.

An 18-year-old who had attacked him — who was supposed to be locked in Room 10 — had stolen Young’s keys, scaled the facility’s fence and sped off in Young’s car.

“When I woke up, I didn’t have my wallet or keys,” said Young, 53, who recounted the incident in an interview Tuesday. “I banged on the door for a while. The officer next door heard me banging, banging, banging and came and got me.”

The escape Monday morning from the New Beginnings Youth Development Center in Laurel has heightened concerns about staffing and security at the state-of-the-art facility, which has had three escapes since it opened in May 2009.

D.C. Council Member Jim Graham (D-Ward 1), who oversees the District’s Department of Youth Rehabilitation Services (DYRS), said Tuesday that nine cameras, which he said should have been actively monitored in a control room, captured the assault and escape. He said the two youths used the guard’s stolen electronic key card seven times. It is unclear when or how the escape was first detected.

“We’re having an intense revelation of how insecure the facility is,” Graham said. “We have got to take immediate steps to make sure it’s a secure facility.”

On Tuesday evening, the 18-year-old had not been found by authorities. Graham said the youth is from Southeast Washington and was being held on burglary and theft charges. He said the youth had been written up dozens of times since May for breaking facility rules, infractions Graham said should have sparked additional intervention.

The teen initially was thought to be 17, but Graham said Tuesday that he had recently turned 18. The second teenager did not leave the facility and was caught.

Christopher Shorter, chief of staff for the DYRS, said that the attack was caught on video and that his staff is conducting an internal investigation, which should be completed in several weeks. He declined to offer additional details about the incident, citing the ongoing investigation.

Young, who has more than two decades’ experience as a guard, said he was escorting a detainee back to his room from a bathroom break about 12:30 a.m. when he was attacked.

“I was shocked. It was like a bad dream,” said Young, whose eye is swollen shut and who will have to undergo facial surgery.

Like other officers on staff, he was by himself on a unit with nine or 10 inmates during the overnight shift, he said.

“I wish we had more staffing on midnights,” he said. “It wouldn’t have happened if we had more officers.”

Young has worked for New Beginnings since it opened. Before that, he worked for its predecessor, Oak Hill, for 20 years. Oak Hill was closed after decades of problems, and New Beginnings opened with high expectations.

Although the aim of the center is to rehabilitate the detainees, Young said the youths can be violent.

“A lot of them are really dangerous. We have to treat these guys like it’s maximum security,” Young said. “I know it’s supposed to be a treatment facility, but we have to be aware of what they’re capable of.”

After they attacked Young, the teenagers took his swipe card to leave the unit and grabbed a ladder left by a maintenance crew, officials said. One held the ladder and the 18-year-old scaled it, Young said.

The youth who held the ladder decided not to make a run for it, Young said.

Young’s car, a Hyundai Genesis with Fraternal Order of Police license plates, was found in the Barry Farm neighborhood in Southeast on Monday afternoon, he said.

Young said he’d never been attacked before. He knew the escapee for six months and had never had a run-in with him.

“It was an opportune moment for him to escape,” Young said. “He was going to make sure nobody was in his way.”

Young’s wife, Karen Young, said officers need better protection.

“I’m somewhat angry with the guy who did this to my husband, but my anger is really with the facility,” she said. “They put him in that position.”