An 11-year-old boy whose mother thought he was asleep in bed was arrested for allegedly breaking into a gun shop with a boulder and stealing 14 semiautomatic weapons and 250 rounds of ammunition.

The boy, who wasn't named, and four teenagers attempted to pull off the dramatic heist of the Suburban Armory in the Philadelphia suburb of Collingdale, according to Collingdale Police Chief Robert Adams.

Among the others in the posse: a 15-year-old and a 16-year-old boy, who also weren't identified; 18-year-old Khalik Keyser of Chester, Pa., and 19-year-old Leroy Taylor of Philadelphia.

They traveled on public transportation to the gun store, gaining entry at about 11:45 p.m. Monday by disabling the alarm system and hurling a boulder through a window, police said.

The five filled allegedly stole 14 semiautomatic weapons, about 250 rounds of ammunition and the shop owner's loaded .38-caliber handgun that they stuffed into school backpacks.

But their plan didn't include a getaway car, according to the Philadelphia Daily News. Two of the suspects were caught at a nearby pizzeria and another two at a bus stop. The 11-year-old was nabbed on a bus that got stuck in traffic.

No one was hurt in the attempted burglary, and all five are still in custody, Adams told FOXNews.com. Keyser is behind bars on $200,000 cash bail and Taylor is in jail on 10 percent of $200,000 bail. The two have been charged with burglary, criminal trespass, theft and other offenses.

Keyser has a criminal history and is on probation after pleading guilty in 2005 to attempted murder and weapons charges in Philadelphia, according to the Daily News.

The 11-year-old and the other two teens will likely not be charged as adults, according to Adams.

"All three juveniles will probably stay in juvenile court," Adams said. "There was no violence committed, and no one was hurt. It was an empty building."

Click here for more on this story from the Philadelphia Daily News.

FOXNews.com's Catherine Donaldson-Evans contributed to this report.