Nine juveniles have been charged in connection with a string of 30 armed robberies across Minneapolis over a five-day period in early February, followed by another rash of robberies in the city last weekend.

Hennepin County Attorney Mary Moriarty announced the charging decisions Friday in a video statement explaining how her office handled the cases and helped Minneapolis police in identifying and charging the youth involved. Police referred a dozen juveniles to Moriarty's office for possible charges.

"If we are brought cases with proof where youth are committing violent crimes, we will charge them and hold them accountable," Moriarty said in the video.

Minneapolis police believe the first onslaught of robberies were committed by youth who had stolen a car or cars. The agency referred five cases, and four minors were charged. But Moriarty said none of the youth were charged for the robberies that occurred.

"It's important to understand that simply because a youth may be found in a stolen car does not mean that we can prove that they stole the car. It also doesn't mean that they were in the car at the time it was used to commit a robbery," she said.

Two supervisors in Moriarty's office pored over the 30 police reports to identify patterns. When the next rash of robberies hit the city Feb. 25, police referred seven cases and prosecutors charged five. Moriarty said the seven kids were not involved in any of the previous robbery cases.

Police Chief Brian O'Hara said in a statement Friday that while it's disappointing when cases referred to prosecutors are not charged, he appreciated the partnership between the county attorney's office and Minneapolis police investigators.

"I continue to be proud of the great police work our officers and investigators do around the clock to address the recent rash of violent robberies committed by juvenile offenders," O'Hara said. "Our investigators continue to work around the clock to identify all of the different juveniles involved and collecting evidence to build cases.

"I am confident the MPD strategy is working. I'm also confident we will continue to make more arrests and present more cases for charging."

The Star Tribune does not typically name juveniles, despite their court cases being public, unless prosecutors signal their intent to certify them as an adult. One of the robbery cases is nonpublic because the juvenile is under 16, and another case is nonpublic because it didn't result in a felony-level offense. That juvenile, who is over 16, was charged with fleeing on foot, a misdemeanor offense. Under state statute, a delinquency or extended jurisdiction juvenile case is public if the person is at least 16 and the offense is a felony.

According to the charges:

Police responded to a carjacking at gunpoint Feb. 9 on E. Lake of the Isles Parkway. The victim said she was sitting in the driver's seat of a BMW rental car around 9 p.m. when three males approached her. One shattered her window and another pushed a gun against her arm and told her to get out or else he would shoot. They pulled her from the vehicle and fled.

Later that night, police spotted another stolen vehicle that was being trailed by the BMW. Officers initiated a pursuit and the BMW crashed into two unoccupied cars. Two males fled through the alley between Irving and Humboldt avenues N. Officers searched the area and found a suspect hiding. Upon arrest, police recovered a handgun on a 17-year-old from Brooklyn Park. The teenager was charged with felony gun possession, fleeing on foot and riding in a stolen vehicle, a misdemeanor.

On Feb. 11, a Kia Sportage was stolen from a church parking lot at 39th Street and Nicollet Avenue in south Minneapolis. The officers spotted the car and pursued it for seven minutes on Lowry Avenue until the vehicle crashed on Plymouth Avenue N. Two passengers fled and one dropped a firearm on the sidewalk. The driver, a 16-year-old from Minneapolis, attempted to flee but was caught by a police dog. He was charged with fleeing in a vehicle, theft of a vehicle and fleeing on foot.

A short while later, police arrested the passenger, another 16-year-old from Minneapolis, who dropped the gun. He was charged with felony possession, fleeing on foot and riding in a stolen vehicle.

Police responded to a robbery spree Feb. 25 involving a Mazda occupied by juveniles armed with guns. A 17-year-old from Richfield was charged with three felony counts of aiding and abetting first-degree robbery and unlawful gun possession.

Three 17-year-olds from Minneapolis were charged Monday with simple robbery, and aiding and abetting simple robbery, in connection with the theft of a vehicle the night of Feb. 26. A woman was walking to her apartment on Girard Avenue S. when a group of four males ran up behind her and stole her keys. Police found the vehicle occupied by the suspects later that night and arrested them.