The phone call that Sa'Lesha Beeks spent months longing for came on Monday.

She was being summoned to police headquarters in downtown Minneapolis for an update about the ongoing investigation into the drive-by shooting death of her mother, Birdell Beeks. The news was good, the detective assured her.

At the police station, Chief Janeé Harteau said she and Beeks shared a "good cry" at the news: There had been an arrest.

"I would have never stopped until we got justice for my mom," Sa'Lesha Beeks said, recounting the conversation at an emotional news conference at City Hall.

"I'm sorry, I'm overjoyed, the feeling is amazing, these are bittersweet tears," she said, trying to compose herself as she spoke to reporters.

Her mother's death in May 2016 set off a rallying cry against gang violence on the city's North Side, after the 58-year-old neighborhood matriarch was struck by crossfire while driving her teenage granddaughter to an appointment. The case was assigned to two detectives, Sgts. Chris Thomsen and Charles Green, who spent months turning the case inside and out and looking for missed clues. On Monday, they made an arrest.

A 20-year-old man was booked into the Hennepin County jail on suspicion of second-degree murder. The suspect, who has ties to the Low End-affiliated Skitz Squad gang, is being held in lieu of $1.5 million bail. He is expected to make his first court appearance on Tuesday.

Although the Star Tribune generally does not name suspects until they are charged, Police Chief Janeé Harteau said the preliminary information was sealed out of fear of retaliation. Harteau said that although they believe they have the right man, the investigation remains open.

"I do not want the justice for one family to cause violence and sadness and tragedy for another," Harteau said. "We do believe that no one intended for Birdell to be the victim."

The arrest brought some comfort to Sa'Lesha Beeks, who had mounted a monthslong crusade to find her mother's killer, appealing nearly daily over social media to the consciences of those who may have information about the case but were reluctant to speak up.

As the months passed, her messages grew more urgent.

"Heartbreaking to see the many shootings that have taken place over the weekend. Especially the few near where our beloved Mother was [murdered] on May 26, 2016," she wrote in one of her last posts. "I pray that some information comes forth from these tragedies in our Mother's case."

In the meantime, she left countless messages for Thomsen and Green, insisting on regular updates. Police offered a $10,000 reward for information leading to an arrest.

As thrilled as she was at the news, Beeks told reporters that it reopened the heartache over her mother's death.

Birdell Beeks was driving back from an appointment with her 16-year-old granddaughter on May 26, 2016, when gunfire erupted as her minivan pulled up to a stop sign at the corner of Penn and 21st Avenues N. She was hit several times and died at a nearby hospital.

Detectives said at the time that she had been caught in the middle of shootout between rival gang members, over what no one was sure. They said it was unclear whether she even had a chance to react.

Police had few leads. Reluctant witnesses were interviewed and re-interviewed, but investigators had little to go on.

"When somebody does something like this, they don't usually go bragging about [killing] an elderly woman," Thomsen told reporters on Monday.

"We still have information about retaliation in the future; that's why this case was sealed," he said.

Harteau said Monday that even in a year when gun violence increased significantly, the death had resonated more than others because of "the innocence factor."

"This was truly an innocent victim" who had done nothing other than be in the wrong place at the wrong time, she said.

Police records show that while homicides are down, 344 people were shot across the city last year, the highest number since 2007 and a sharp increase over the roughly 260 injured by gunfire in 2015.

Harteau said that investigators were seeing the same faces over and over among both suspects and victims, more than half of whom have gang ties.

Beeks, who has since moved out of north Minneapolis, said she would continue her crusade to solve the community's crime problem.

"I will not stop my fight," she said. "My fight continues for safety in north Minneapolis."