Video (03:38) : Police announce arrest of suspect in 2015 slaying of popular north Minneapolis activist. The high-profile slaying remained unsolved for four years.

An 18-year-old man has been arrested and charged with the 2015 home invasion murder of Susan Spiller, a prominent north Minneapolis community activist and artist whose death shocked the city with its brutality and seeming randomness.

At a City Hall news conference Tuesday, officials said they arrested the teenager. But, because he was 14 at the time of the murder, officials said they could not go into details of the case, including information on a motive. The suspect, who made his first court appearance Tuesday, has been held at a juvenile facility since his arrest the day before.

Prosecutors are seeking to certify him as an adult because of the seriousness of the crime. Until then, court proceedings must remain private, officials said.

At the news conference, Police Chief Medaria Arradondo singled out the doggedness with which the three assigned detectives — Sgts. Ann Kjos, Luis Porras and Chris Karakostas, with more than 35 years of combined Homicide Unit experience between them — pursued the case. Investigators eventually linked a set of fingerprints found at the scene to the suspect, who had recently been arrested in an unrelated crime, officials said. "This team of devoted and experienced detectives never gave up on this case," he said.

Authorities on Tuesday released few other details about the circumstances of Spiller's death, but said forensic evidence put the suspect at the scene.

"That did not happen until just recently, and it came up after the suspect turned 18 and those fingerprints were taken up in an unrelated case," said Tom Arneson of the Hennepin County Attorney's Office.

Tom Arneson, managing attorney for the Hennepin County Attorney's Office juvenile division, spoke at a press conference to announce the arrest of a suspect in the 2015 murder of Susan Spiller. Minneapolis Police Chief Medaria Arradondo listened.

News of Spiller's death rocked the normally placid Lind-Bohanan neighborhood that she called home.

"That neighborhood was forever changed," Arradondo said, offering his condolences to members of Spiller's family, including son Jason, who mounted a monthslong crusade to find his mother's killer. "Ms. Spiller was an artist and a community activist — while her death shocked many, it was Susan Spiller's life and spirit that has inspired her community and our entire city of Minneapolis."

Spiller, a friend of former longtime City Council Member Barb Johnson, was killed during an apparent home invasion on the morning of July 16, 2015. Her body was found by officers who described a gruesome scene inside her modest wood-frame house in the 5100 block of Dupont Avenue N. Her injuries were so extensive that medical examiners were unable to pinpoint a precise cause of death, ruling instead that she died of "complex violence."

The case languished for years, with a police reward for information going unclaimed.

Meanwhile, the investigation continued. Detectives targeted several suspects, but each was ruled out early on. Police briefly eyed a teenager with a long history of run-ins with the law but didn't immediately interview him because investigators couldn't locate him. They also questioned a neighbor with whom Spiller had apparently had a confrontation shortly before her death that left her shaken and fearful.

The announcement Tuesday came shortly after the sentencing of a man in another high-profile cold case: the killing of Lorri Mesedahl, 17, whose body was found in a North Side rail yard in 1983 after she had been strangled and brutally beaten. Her killer, Darrell Rea, was sentenced Tuesday to more than 10 years in prison for her death.