Mark Donnelly is one of the last names that would come to Adam Browns’ mind if he heard one of his friends had been shot dead in a spate of sudden senseless urban violence.

“Just shocking. I can’t believe it,” Brown, Donnelly’s longtime friend and fellow graffiti artist, said Tuesday. “Mark would never do anything to get shot.”

Brown, the 27-year-old owner of Streetwise Graffiti Bike & Skate on Nashua’s Temple Street, is part of the wide circle of family, friends and acquaintances mourning the loss of Donnelly, who died late Saturday night shortly after being shot during a confrontation near Pine and Prospect streets in Manchester.

As police continue combing evidence in the search for his killer, those close to him have set up a fund to help offset funeral expenses and to assist his two daughters, ages 2 and 7. They are also in the midst of planning a two-day benefit at Nashua Car Wash, 86 Broad St., which will direct its Thursday and Friday proceeds to the fund.

Donnelly, 31, described as a talented street artist, “a special guy,” “awesome friend” and “the hardest, and best, worker I’ve seen in a long time,” was shot by an unknown assailant after he and two friends exchanged words with people inside a car that stopped where they were walking.

The attorney general’s office said Tuesday that a state medical examiner’s autopsy shows Donnelly died of a single gunshot wound to the chest. The cause of death was ruled homicide, officials said.

Neither the Attorney General’s office nor Police Chief David Mara provided further details, stating only that “no arrests have been made … and the investigation is ongoing.” They ask that anyone with any details on the incident contact the Manchester police detective unit at 668-8711 or call Manchester Crimeline at 624-4040.

The shooting capped what some witnesses described as a confrontation that began when a woman approached Donnelly and a friend asking for money. Officials didn’t report on what was said or what prompted the assailant to raise a handgun and fire shots.

A neighbor who looked out her window upon hearing the shots said she saw a man, later identified as Donnelly, fall to the sidewalk. Friends surrounded him, said the woman, who watched as police and medical personnel arrived.

Brown said he’d known Donnelly for several years before the two became fast friends in high school. “I’d heard of Mark before; he was very well known for his art,” Brown said of Donnelly’s reputation as a talented street artist.

“I hadn’t seen him much lately; he was focusing mostly on work and his kids,” Brown said.

Although Donnelly is well-known for his art, he also had a few run-ins with police in the past.

In May 2002, Donnelly, then 20, was sentenced to two consecutive eight-month terms in the Hillsborough County Department of Corrections, about 10 months after he and a Hudson man were convicted of arson for starting a fire that destroyed a storage trailer and contents belonging to the Independence Rowing Club.

Donnelly and the other man, identified as Timothy Bagley, also 20 at the time, also admitted to setting four other fires in Nashua between October 2000 and July 2001.

They were ordered to pay $102,000 total in restitution to the rowing club, write letters of apology and perform 100 hours of community service.

A Telegraph story in February 2004 reported Donnelly’s arrest following “a high speed chase from Nashua into Merrimack” that began when a bicycle officer tried to stop the car Donnelly was driving after noticing none of the young passengers were wearing seat belts. The 11-minute chase began on Main Street near High Street and ended on Daniel Webster Highway in Merrimack, the story states. It reached speeds of 80-90 mph on the F.E. Everett Turnpike.

Police said Donnelly told them he refused to stop because he had a problem with the status of his driver’s license and “shouldn’t have been driving.”

A Nashua native, Donnelly lived in Nashua until two years ago, when he moved to Manchester to live with his girlfriend, Vanessa Hall. Their daughter, Madyson Jeanne, was born shortly after that. Donnelly and Hall became engaged just over a year ago, on May 3, 2012, according to their Facebook pages.

Donnelly’s other daughter, 7-year-old Haleigh, lives with her mother in northern New Hampshire.

Beginning Sunday morning, numerous social media posts carried condolences, memories and words of support for those close to Donnelly.

Brown said he felt compelled to see the spot where his friend died. “I went up there, looked around the place he was shot,” he said of the Manchester crime scene. “It’s not a bad neighborhood at all. It looked quiet there. As soon as I found out it was Mark (who was killed), I knew it had to be over nothing.

“If there was a fight … even if they jumped him, it would only have been a fight. It would have been over. Nobody would have died. Mark died over nothing.”

Donnelly’s work will live on, Brown said, in scores of canvases he painted for friends over the years. Canvases are smaller, portable versions of graffiti artists’ work.

“He did hundreds of them,” Brown said, pointing to three such works hanging on the wall at Streetwise.

Looking back, Brown laments the fact Donnelly never got around to applying his signature to Brown’s space. “We did a lot of stuff – filming, painting together,” he said. “But I really wish he got a chance to paint on my wall.”

Dean Shalhoup can be reached at 594-6443 or dshalhoup@nashuatelegraph.com. Also, follow Shalhoup on Twitter (@Telegraph_DeanS).