A judge on Monday ruled that a Hastings teenager was justified when he stabbed to death a much-larger teen who, high on methamphetamine and alcohol, had chased him to a school yard in the middle of the night and slashed him with a knife.

Allan Beckles, 17, had claimed self-defense in the slaying of his one-time friend, Trenton Griebling, 16, in August. Griebling's family was stunned by the acquittal.

"We are just dumbfounded how this could happen," said the victim's father, Chris Griebling of Hastings.

"I lost a lot of faith today in our judicial system," he said. "I've just always believed that it was honest and fair. I lost respect for it today, and that makes me sad."

Beckles, who was tried as a juvenile, waived a jury trial so that the case was heard by Dakota County Judge Patrice Sutherland.

In a 17-page verdict, she said teen witnesses who had fingered Beckles -- who was subsequently charged with second-degree unintentional murder -- later admitted lying, and she noted "puzzling" test results on a bloody towel done by a Bureau of Criminal Apprehension (BCA) scientist.

After he was acquitted, Beckles was released from jail, where he had been locked in a juvenile section for six months.

"He wants to fade back into the woodwork," said Beckles' attorney, Lawrence Nichols. "He's got to live with this for the rest of his life. It's a justifiable homicide from a legal standpoint. And if he hadn't killed this kid, this kid would have undoubtedly killed him."

Nichols had criticized the BCA scientist for not thoroughly testing a bloody towel that Beckles had used to wrap his slashed arm.

The scientist had determined that Griebling's blood was on that towel. But that perplexed police, who asked the scientist to check again for Beckles' blood, which should have been on it.

The scientist told police that she didn't think it was important to conduct more testing, but she later admitted in court that her findings were puzzling.

Frank Dolejsi, lab director at the BCA, said the scientist was unavailable for comment.

On any particular case, scientists "are not able to test every little spot of blood or every piece of evidence that we may get," Dolejsi said Monday after the verdict.

The judge noted that many juvenile witnesses in the case had changed their stories. Most had been using drugs or alcohol when the killing occurred, according to testimony.

But Beckles, the judge said, stuck to the same account of how Griebling came after him.

Dakota County Attorney James Backstrom on Monday voiced disappointment with the verdict.

A peacemaker, father says

Griebling's father said that his son had been a peacemaker, always trying to break up arguments, and that his family still believes that's how he died, trying to settle a skirmish brewing between Beckles and other teens, who were after him.

In the year before he was slain, Trent Griebling, a lanky redhead, had been lifting weights, running and trying to take care of himself, his father said.

The teen had started using illicit drugs when he was 14, and he'd been through treatment. But an autopsy showed that he had levels of methamphetamine in his system so high that it was halfway to a lethal level, and that he was also drunk.

Still, his father stands by the belief that Trent Griebling was the victim.

"I know that he wasn't the aggressor," his father said. "I know he was honestly down there trying to defuse some problems that were going on with the kids. I think he was just in the wrong place at the wrong time."

Joy Powell • 952-882-9017