The shooting death of a 19-year-old Hamline University student was the fourth instance in a week in which a victim was lured in St. Paul by someone advertising an iPhone for sale on Craigslist, police said Monday.

Aung Thu Bo died Saturday after being shot in the head in the Dayton's Bluff neighborhood Friday while his assailant tried to search his pockets for money.

"This was a senseless and violent murder, and our hearts go out to the victim's family and friends," County Attorney John Choi said Monday. Bo's shooting was the third high-profile killing linked to Craigslist in the metro area in recent years.

Steven E. Lewis, 26, of Maplewood, was charged in Ramsey County District Court with second-degree murder and aggravated robbery in connection with Bo's death. Bo, described by friends and neighbors as a willing volunteer with a kind heart and a head for computer science, would have been a sophomore at Hamline this fall.

The three earlier robberies at gunpoint occurred Aug. 3-4 in St. Paul, and in one case the victim -- an Oakdale resident -- was hit in the mouth with a gun, police spokesman Howie Padilla said. Like Friday's robbery, that incident, on Aug. 4, took place in the afternoon not far from Dayton's Bluff Recreation Center.

Police were investigating similarities in the cases, Padilla said.

In the St. Paul neighborhood where Bo lived with his parents and three younger sisters, relatives and friends came and went quietly Monday from the one-story, sand-colored house surrounded by neatly kept flower beds. A family friend said the parents were overwhelmed with shock and making funeral arrangements.

Neighbors had only kind words to say about the slain college student.

"He was an awesome kid," said Julie Hartigan, who first met Bo when he was a boy, not long after he and his family settled as new immigrants on Hubbard Avenue, just off Lexington Parkway.

His parents had left their native Burma during fighting there, she said. They stayed in a refugee camp in Thailand, where Aung was born, before making their way to the United States on a church sponsorship.

Aung's parents, mother Thanthan Aye Bo and father Win Bo, reared their children "to be respectful and thoughtful and kind, and you just don't see that a lot anymore," she said of Aung and his sisters.

Aung spent countless hours volunteering at a nearby nursing home, where his mother worked in the dietary department, Hartigan said. Her daughter, Emily Nelson, 18, said that Bo wanted to be a computer engineer and was "super-smart."

"We are deeply saddened by the loss of one of our undergraduate students, Aung Thu Bo," a posting on Hamline University's Facebook page said. "Faculty, staff and friends who knew him say he was a smart, thoughtful person who always tried to be helpful and kind."

'Give me what you got'

According to the complaint, Bo and his girlfriend met Lewis in the parking lot of Leo's Chow Mein on Old Hudson Road on Friday afternoon to buy a cellphone that Lewis had advertised on Craigslist. Lewis persuaded them to drive to his house nearby to retrieve the phone's charger as well as the phone.

Bo was hesitant, saying he didn't do transactions at houses, but relented.

Shortly after getting into the car behind Bo, Lewis pulled a gun at Cypress Street and Wakefield Avenue and demanded, "Give me what you got," according to the criminal complaint. Bo had trouble finding his wallet and said his money was at the bank.

With the gun held to Bo's right temple, Lewis leaned forward to search his pockets, and the gun fired. Lewis ran from the car, which began rolling forward. Bo's girlfriend brought the car to a halt, screamed for help and applied pressure to his wound.

Officers used a description of the defendant and reports of similar robberies in the area to track a Pontiac Grand Am to a residence on Plum Street. They found Lewis in the vehicle, talking on his cellphone with blood on his hands and apparent bullet wounds to his forearm, the complaint said.

The officer reported that he heard Lewis say upon his arrival: "I love you, and tell the girls I love them. I'm going away for a long time."

Officers recovered an ammunition magazine for a Glock handgun and several cellphones at the house.

Lewis told police that someone had shot him after he bought juice at a market and that he had had nothing to do with Bo's killing. "Lewis, apparently realizing the inherent stupidity and inconsistent logic of his claim, then asked for a lawyer," the complaint read.

Bo was removed from life support at Regions Hospital on Saturday.

Lewis' criminal history in Minnesota includes felony convictions for damage to property, theft and domestic assault, along with misdemeanor convictions for fifth-degree assault, domestic assault and receiving stolen property. According to state records, he has faced charges in Ramsey County nearly every year since turning 18 in 2003.

He remains jailed in lieu of $500,000 bail.

The two other high-profile Craigslist killings in the metro area also involved deception and guns.

In September 2010, Dao Xiong shot and killed Youa Ty Lor, a Maplewood man who had advertised a sports car for sale. Xiong talked Lor into taking the vehicle on a test drive in rural Lake Elmo, where he lured Lor to a ditch, shot him in the abdomen and left him to die. Xiong was convicted in August 2011. Michael J. Anderson became known as the Craigslist killer in October 2007 when he shot 24-year-old Katherine Olson, who replied to his ad seeking a baby sitter. He was convicted in March 2009.

Star Tribune staff writer Paul Walsh contributed to this report. Anthony Lonetree • 651-925-5036 Joy Powell • 651-925-5038 Tim Harlow • 651-925-5039