Story highlights William Chapman's mother tells ex-officer: "You took a life, and now you're life is gone"

Stephen Rankin is fired; Portsmouth police chief expresses faith in the grand jury process

Rankin's lawyer says "the facts do not support" a first-degree murder charge in this case

(CNN) A grand jury has indicted Portsmouth, Virginia, police Officer Stephen Rankin on a first-degree murder charge related to the shooting of an unarmed teen in a Walmart parking lot, according to public Virginia court records.

William Chapman, 18, was fatally shot on April 22.

Police responded to a shoplifting call at a Walmart, after which the officer approached Chapman, according to Jon Babineau, an attorney for the teen's family.

There was a struggle between the officer, who has been fired, and Chapman before the shooting, according to a witness.

"The guy charged at him -- like took two steps toward him to come fight him, so the cop opened fire," a witness told CNN affiliate WTKR.

Read More