North Charleston, SC (WCIV) — The Charleston County Coroner's office has identified a man shot and killed in North Charleston the day after Christmas.

DeTwan Walker, 20, was shot to deathon Wednesday, December 26, authorities say.

Walker's death was originally treated as a suicide, but North Charleston Police said Dec. 28 they were conducting a homicide investigation.

Walker's girlfriend said she'd been in a conversation with him moments before the shooting, according to police. The girlfriend told police Walker stepped out on the porch of their Navajo Street residence, and she heard a gunshot moments later.

The North Charleston Police Department is still investigating.