Samuel Johosephat Taylor, whose troubles with guns and the law began as a teenager, won several second chances from the juvenile justice system. And last month, he was given one more.

A Hennepin County district judge allowed Taylor to remain on supervised probation after he admitted that he had violated terms of that probation for a January 2010 armed robbery conviction, court records show.

Three weeks later, Taylor shot and killed a cabdriver in north Minneapolis, according to a criminal complaint filed Thursday.

The 20-year-old Robbinsdale man has been charged with one count of second-degree murder in connection with the killing of William Harper while the driver was stopped in his taxi near 400 23rd Av. N.

Taylor is in the Hennepin County jail after turning himself in to the police late Tuesday, authorities said.

Records from Taylor's Feb. 23 court appearance don't show what probation terms he violated, but they indicate Judge Kathryn L. Quaintance required community service and supervised probation but didn't send him back to a correctional facility.

"He made a court appearance about the violation, and the court's determination was that he would continue on his ... probation," said Chuck Laszewski, a spokesman for the Hennepin County attorney's office.

Court records reveal that Taylor was first charged with a felony at 16.

He faced several charges of making terroristic threats after an acquaintance alleged that he threatened her and was seen waving a gun and saying, "I'll smoke that [expletive]." Authorities dismissed the charges on condition that Taylor be placed on probation until age 19 and attend counseling programs.

He was also charged as a teen with marijuana possession and fleeing a police officer.

On Jan. 3, 2010, days before his 18th birthday, records show, Taylor charged into a hotel room party at a Brooklyn Center Days Inn and brandished a semiautomatic handgun. He ordered the people there to empty their pockets. Then he beat up an acquaintance and stole his cellphone. The acquaintance told police he was known to them as "Smack," a moniker that was also tattooed on Taylor's biceps.

He initially denied committing the robbery, noting that his right foot was bandaged from a gunshot wound. Taylor later pleaded guilty to two counts of aggravated first-degree robbery.

Taylor's seven-year sentence was stayed until his 21st birthday under the condition that he be placed in a program for juvenile male chronic offenders at Red Wing prison.

A psychological evaluation filed with the court said Taylor needed help in managing illegal chemical use, treating ADHD and developing "prosocial skills."

But Taylor struggled in the program and expressed frustration with his placement there, according to documents filed in July 2011.

Even so, he was released from the facility in November and placed on probation with a requirement to get counseling and attend classes so he could work toward a diploma.

After agreeing in his February court hearing to abide by his probation, Taylor missed a required meeting with a community specialist March 13, records show. The next day, Taylor missed an appointment with his probation officer.

At 9:37 p.m. that night, March 14, Taylor called Yellow Cab for pickup at 3543 6th St. N., a witness told police, according to the criminal complaint. He had a gun on him, according to the witness.

A man told police he heard a gunshot and saw someone running in the alley between 6th Street and Lyndale Avenue N, according to the criminal complaint. The man running away was shoving a gun into the front of his pants.

Police officers responding to a shooting call discovered Harper on the ground next to the driver's door of the cab calling out, "Help me, I've been shot."

Medical examiners determined the bullet hit him in the back and exited his chest. Harper was taken to North Memorial Medical Center in Robbinsdale and pronounced dead later that night. The Roseville man was 56.

A woman told police that within hours of the shooting Taylor said to her "that he was committing a robbery and he shot someone," the complaint said. The witness told police that Taylor changed the appearance of his hair because someone saw him running away, and also washed and bleached his hands, according to the complaint.

A warrant was issued for Taylor's arrest on March 15 for violating his probation.

Five days later, he turned himself in.

Maya Rao • 612-673-4210