After less than three hours of deliberation Wednesday, a Baltimore jury found John Alexander Wagner guilty of first-degree murder and armed robbery in the stabbing of Johns Hopkins researcher Stephen Pitcairn, who was attacked last year as he talked to his mother on a cellphone while walking home from Penn Station.

Wagner could receive a maximum sentence of life in prison at a hearing set for Oct. 21. His lawyer, Assistant Public Defender Gregory Fischer, said he plans to appeal the conviction.

"Mr. Wagner has adamantly maintained his innocence from the beginning," Fischer said.

Pitcairn's family members, who live out of state, wept as the verdict was announced. Aunts and uncles, as well as his parents and siblings, sat vigil throughout various portions of the trial, enduring as much testimony as they could. They declined to comment after the hearing, though Pitcairn's uncle called out, "Justice was served" as he left the courthouse.

They also praised the work of Assistant State's Attorney Josh Felsen after the hearing, telling him to "take care of the next family as well as you took care of us."

It was a bittersweet victory for the city prosecutor's office. Attorneys finally won a significant conviction against Wagner, who had repeatedly escaped serious punishment despite a lengthy criminal history, but it came at the cost of a promising young man's life.

"This victim … wasn't bothering anyone, he wasn't doing anything but walking to his home," Felsen told jurors during closing arguments Wednesday.

Pitcairn was two days shy of his 24th birthday on Sunday, July 25, 2010, the day he was killed. He spent the weekend with his two sisters in New York City for an early birthday celebration, then took a Bolt bus back to Baltimore, where he performed cancer research.

But as he walked along the 2600 block of St. Paul St. talking to his mother on his cellphone, he was targeted by Wagner and his girlfriend, Lavelva Merritt — who has pleaded guilty to her role in the killing and testified for the prosecution last week. They robbed Pitcairn, stabbed him and left him to die on the sidewalk.

Pitcairn's mother, meanwhile, frantically tried to find help from her home inFlorida after hearing the commotion. Gwen Pitcairn tearfully told jurors last week at the trial's opening that she pleaded for her son's safety to the voices demanding money from her son, a thousand miles away in Baltimore.

The murder was a focus of last year's Baltimore state's attorney race and helped challenger Gregg L. Bernstein unseat longtime incumbent Patricia A. Jessamy.

Bernstein held a campaign news conference on what would have been Pitcairn's birthday, railing against Jessamy's failure to keep violent repeat offenders off the streets.

"If the state's attorney had done her job ... Stephen Pitcairn might still be alive today," Bernstein said at the time, calling the murder "not just senseless, but preventable."

He said in a telephone interview Wednesday that his office was "extremely gratified" by the jury's verdict.

"The defendant represents one of the focal points and objectives of our office, which is to successfully prosecute repeat violent offenders and ensure that they are incarcerated for substantial periods of time so that they do not continue to go through this revolving door and prey upon the citizens of Baltimore," Bernstein said.

Wagner, 38, has previous convictions for assault, theft and violating probation, though he was frequently allowed to remain free. And in at least one instance, prosecutors dropped robbery charges against him despite surveillance video evidence.

Merritt, 25, has at least five convictions on her record, most for drug offenses.

The case against Wagner largely relied upon her cooperation. Testifying against Wagner, she outlined a chilling scenario in which the couple set out looking for someone to rob. They came up behind Pitcairn and grabbed him, demanding money.

Wagner stabbed Pitcairn, and Merritt punched him after he fell, according to testimony. They took his iPhone and his wallet, a Christmas gift from his mother.