MINNEAPOLIS — Authorities have arrested an 18-year-old man in the brutal killing of a Minneapolis activist in 2015.

The man was 14 at the time of Susan Spiller's murder. His name is not being released and authorities could say little Tuesday because he was charged as a juvenile.

Prosecutors say investigators got a break in the case after the man committed another crime — his fingerprints from that case were found to match the fingerprints at the murder scene.

The man is charged with second-degree murder. Prosecutors have petitioned to have his case moved to adult court.

Spiller was found dead in her home on July 16, 2015. She was so badly injured that an exact cause of death could not be determined and the medical examiner found she died of "complex violence."