A suburban Detroit man was sentenced Wednesday to at least 17 years in prison for killing an unarmed woman who appeared on his porch before dawn.

Theodore Wafer was convicted of second-degree murder in the Nov. 2 death of 19-year-old Renisha McBride. Before he was sentenced, the Dearborn Heights man apologized to her family, saying he killed a woman who was "too young to leave this world."

Wafer is white and McBride was black, and some wondered in the aftermath of the shooting whether race was a factor, likening it to the shooting of Florida teenager Trayvon Martin. But race was hardly mentioned at trial.

"I will carry that guilt and sorrow forever," said Wafer, often pausing to control his emotions.

Wafer was convicted last month after a nine-day trial that centred on whether the 55-year-old had a reasonable and honest belief that he was in peril. He testified that he was awakened by pounding on his doors and shot McBride because he feared for his life. A jury rejected his claim of self-defence.

Prosecutors recommended at least 17 years in prison for Wafer, the low end of the guidelines, including two years for unlawful use of a gun. Defence attorney Cheryl Carpenter asked for as few as six years in prison.

Porch Shooting

No one knows why Renisha McBride, 19, ended up at Theodore Wafer's home at about 4:30 a.m. on Nov. 2, although prosecutors speculated she may have been seeking help. She had crashed her car into a parked car less than a kilometre away. (Detroit Free Press/Associated Press)

Noting Wafer's age, Carpenter told Judge Dana Hathaway that anything more than 10 years in prison would be a "life sentence."

Wafer, who played football at Northern Michigan University in the 1970s, has health problems after a career as a labourer, including outdoor maintenance at Detroit Metropolitan Airport, Carpenter said. The judge declined to go below the guidelines.

No one knows why McBride ended up at Wafer's home about 4:30 a.m. ET, although prosecutors speculated she may have been seeking help. She had crashed her car into a parked car about a half-mile away in Detroit at around 1 a.m. An autopsy found she was extremely drunk.

Wafer opened the front door and shot McBride in the face, firing through a screen door. He first suggested to police that it was an accident but later admitted to intentionally pulling the trigger.

Renisha McBride

Monica McBride, mother of Renisha, cried during the reading of the guilty verdict in August. (Clarence Tabb Jr./Detroit Free Press/Associated Press)

In Michigan, victims can speak in court before a final sentence is ordered. McBride's sister, Jasmine McBride, criticized Wafer for his "cowardly actions."

The judge said McBride had made "some terrible choices" but that she didn't deserve to be killed.

Hathaway described the case as "one life gone and one life ruined."

The jury convicted Wafer of murder, manslaughter and a gun-related charge on Aug. 7. His maximum sentence is 32 years in prison, although he'll be eligible for parole after serving the minimum of 17.