(If you’re having trouble viewing this video on a mobile device, click here.)

SAN JOSE — A purported crew of teens — and an 11-year-old suspected getaway driver — were arrested after a six-hour spree of armed carjackings and robberies in San Jose over the weekend that echoed a similar case from October.

Related Articles 12 hours of mayhem: San Jose police arrest five in crime spree

The young ages of those arrested startled many veteran officers, but officials say it’s part of a dramatic spike in crimes committed by underage suspects over the past year.

“I have a lot of concern about the rise in juvenile crime in the city, and the violent crime that has been occurring,” police Chief Eddie Garcia said. “We’re not talking about graffiti or knocking down garbage cans or having loud parties. These are adult crimes. These are not kid crimes.”

San Jose police announced Wednesday that they arrested 11 male and female suspects, ages 11 to 17, from San Jose and Gilroy. They are accused in nearly a dozen robberies, carjackings and burglaries, several of which were at gunpoint, at various sites in San Jose on Friday night and Saturday morning, police said.

At least 15 victims have been identified. Investigators said there may be more who have not yet come forward to police.

“We’re still working on piecing it all together,” said Lt. Paul Joseph, commander of the SJPD robbery unit. “We had a whole bunch of crimes happening in a short period of time, and there are similarities between some of them. We want to make sure anyone out there who was victimized comes forward.”

The suspects were arrested after three high-speed car chases with police. An 11-year-old boy who was identified as the driver in one pursuit, police said. The other drivers were 14 and 17 years old.

Police say the violence began with a carjacking in which a woman was thrown from her vehicle at Communications Hill just before 11 p.m. Friday.

Over the next six hours, the suspects traversed the city as five armed robberies, five carjackings and a violent assault occurred, police said. The alleged crimes were reported throughout the city, stretching to downtown, East San Jose and South San Jose.

Three to four members of the crew were involved in each of the attacks, police said, and investigators realized victims and witnesses were describing the same vehicles.

All 11 suspects were booked into Juvenile Hall on suspicion of crimes including armed robbery, carjacking, assault with a deadly weapon, auto theft, evading and reckless driving, and resisting arrest. None has been publicly identified because they are minors.

The case marks the second high-profile arrest of a group of teens in an extended string of violence in San Jose. In October, police arrested an 18-year-old man and four minors after a 12-hour crime spree in which they allegedly shot a homeowner during a botched burglary, broke into several homes, and committed a carjacking.

“This is happening almost every other week,” Joseph said. “It’s different groups and different kids each time. Another group springs up as soon as we arrest the last group.”

Garcia bolstered that trend by citing SJPD figures that show a 69 percent year-to-date increase in juvenile arrests for robbery, from 85 cases at the same point last year to 144 this year. Burglaries in that same demographic have risen by 65 percent, from 79 cases to 130; vehicle theft by that group is up 106 percent, from 60 cases to 124; and overall violent crimes by juvenile suspects are up 42 percent.

“We can’t put our arms around why it’s occurring, we just know it’s increasing,” he said.

The chief added that the suspects’ patterns and motives are not aligning with historical gang affiliations.

“That’s the game changer. They’re not in these validated gangs,” Garcia said. “You can’t put them in a box of what we historically think of as a gangster. Yet these groups of kids are victimizing our community.”

He restated his previous contention that a years-long national movement toward sentencing leniency for teen and young offenders may have inadvertently emboldened more brazen crimes.

“I think it’s a factor,” Garcia said. “I’m sensitive to the fact kids are going to make mistakes, but when they’re committing violent felonies, there needs to be a balance between intervention and consequences.”

Anyone with information about the weekend string of crimes can contact robbery unit Detective Mike White or Detective Katie Reyes at 408-277-4166, or leave a tip with Silicon Valley Crime Stoppers at 408-947-STOP or at svcrimestoppers.org. Tipsters may be eligible for a cash reward.