A 17-year-old Escondido boy who allegedly raped and robbed a 16-year-old girl at gunpoint as she walked to school last week was charged Wednesday under the state's "one-strike" law for sex offenders.

The teen faces 50 years to life in prison if convicted of charges that he raped, robbed and kidnapped the girl while wielding a handgun, Deputy District Attorney Patrick Espinoza said.

The North County Times is not naming the suspect because he is a juvenile.

In a brief arraignment at the Vista courthouse Wednesday, the teen pleaded not guilty to the charges. Superior Court Judge Martin Staven ordered him held on $1 million bail.

Espinoza said the teen is being held at Juvenile Hall in San Diego.

The prosecutor said the suspect is being charged as an adult because of the seriousness of his alleged crimes.

"Because of the serious nature of the crime, because a handgun was used, because a 16-year-old girl was kidnapped on her way to school, that's why we decided to charge the case as we did," he said.

The alleged crimes also qualify the defendant for the possibility of life in prison, Espinoza said.

The state's 1994 one-strike law was passed by the Legislature and expanded under voter-approved Jessica's Law in 2006. It allows child molesters and rapists to receive sentences of 15 years to life or 25 years to life if the crime is committed under particular aggravating circumstances.

Espinoza said the teen's alleged use of a gun and a kidnapping during a rape qualify him for the stiff sentencing of two consecutive 25-years-to-life sentences.

Police said the suspect assaulted his victim as she walked on a bicycle path near the flood control channel off North Ash Street and East Valley Parkway on Friday.

The path is well-used and just behind Fresh and Easy market and other businesses, Escondido police Lt. Craig Carter said.

"It's not exactly a ghost town," he said.

The suspect passed the girl, and when she looked back at him, he had pulled a black ski mask over his face and was running toward her with a pistol, Carter said.

The attacker put the gun to the victim's ribs and walked her behind some bushes about 200 feet away, where he raped her, Carter said.

The next afternoon, an officer spotted the suspect on North Rose Street near Washington Park.

Carter said the officer stopped the teen because he looked like a composite sketch made from the victim's description. The sketch featured the teen's buzz-cut hair and acne-blemished cheeks. Carter said there was something else that drew the officer to the boy, but he declined to say what it was.

The officer learned there was a warrant for the juvenile's arrest and took him into custody.

At the police station, a piece of the victim's stolen property was found in the suspect's possession, Carter said.

Police have interviewed the suspect's father, who lives in Escondido, Carter said Tuesday. He said the suspect dropped out of high school "some time" ago, declining to be more specific.

The lieutenant said detectives are still trying to determine where the boy was living and have not served any search warrants in the case.

He declined to comment on whether police have located the gun allegedly used in the attack, citing the open investigation.

Detectives are reviewing all Escondido rape cases over the past year to see if the teen may be a suspect, Carter said.

He said the 16-year-old victim in last Friday's attack is doing well, considering the circumstances.

"She's a very strong individual," he said.

Call staff writer Sarah Gordon at 760-740-3517.