CHICAGO (CBS) — Police were investigating some discrepancies in a story about a robbery attempt just before woman was killed and her boyfriend was injured when they were hit by a truck on Lake Shore Drive early Sunday in the Gold Coast neighborhood.

The 43-year-old man told police he and 32-year-old Pamela Johnson were walking in the 600 block of North Lake Shore Drive around 1:40 a.m., when they were approached by a group of men, at least one of whom displayed a handgun. He told police the men threatened to rob the couple, so he and Johnson ran away, and into traffic on southbound Lake Shore Drive near Huron Street.

They were hit by a white pickup truck as they tried to run across Lake Shore Drive, police said.

The couple was taken to Northwestern Memorial Hospital, where Johnson was pronounced dead at 2:05 a.m.

Sunday afternoon, police said there were some inconsistencies in the story about the robbery attempt, and investigators were reviewing surveillance video from the area.

Community activist Andrew Holmes said Johnson’s family is skeptical of the robbery story.

“So many ways we as a family – and I’ll just let the chips fall where it lay – we ain’t buying too much of what happened,” he said.

Johnson leaves behind a 12-year-old son. Her family described the pain and loss they feel after her death.

“She was everything to me,” said Johnson’s sister, Ashley. “My heart is broken to pieces. It’s my only sister.”

Johnson’s boyfriend was listed in stable condition Sunday morning.

Area Central detectives and the Major Accidents Investigation Unit were investigating.