A Detroit man has been charged with second-degree murder after he shot and killed an unarmed black woman who was seeking help on his porch following a car accident.

Theodore Wafer, 54, was also charged with manslaughter and felony firearm possession on Friday morning. Renisha McBride, 19, was shot in the face on the porch of Wafer's Dearborn Heights home on Saturday 2 November.

McBride's death sparked anger from her family, who allege race was a factor, and prompted calls for a thorough investigation from civil rights groups. McBride's family has compared her death to that of Trayvon Martin, who was shot and killed by George Zimmerman in Florida in February 2012.

Michigan, like Florida, has a stand-your-ground law that allows a homeowner to use force during a break in. It is understood Wafer has claimed self-defence.

Relatives said she was stunned after the car crash and had been wandering through Dearborn Heights – a mostly white neighbourhood – asking for help.

“I’m feeling this was racist,” said McBride’s aunt Bernita Spinks, who is acting as a spokesperson for the family. She told the local Fox TV station, WJBK: “You see this black African young lady, knocking for help. He didn’t even see what kind of help she was seeking.”

Gerald Thurswell, the McBride family's attorney, said the homeowner called 911 after the shooting and police were there within two minutes.

"If he had called 911 when he heard her outside his house, (the police) would have been there within two minutes and she would be alive today," Thurswell said.

An autopsy released this week ruled that McBride died of a gunshot wound to her face. A toxicology report released Thursday showed she had alcohol and marijuana in her system at the time.

Thurswell said the toxicology report has no bearing on the case.

"Maybe she would have been arrested for being intoxicated, but she would not be dead."

The incident has stirred racial tensions in Detroit. The area of the city where McBride lived with her mother, to the north-west, is 83% black, whereas the suburb of Dearborn Heights is 86% white.

McBride recently started working on the inspection line at a Ford car plant in nearby Dearborn. She was educated at Southfield high school.

“She was sweet. She didn’t get into trouble,” Spinks told the Detroit Free Press.