Miyana Williams was with her paternal grandmother at a church on Harbor Way when, shortly after 8 p.m., an unidentified woman came into the church and took her, according to French.
The woman was not Williams' mother, but the child recognized the person and so did the grandmother, who did not know the woman's name or connection to Williams, French said.
The grandmother confronted the woman, and the two got into an argument that ended when the woman put Williams in a vehicle occupied by two men and left the area, according to French.
The vehicle was described as a four-door Chrysler Sebring that was possibly light blue or green, French said.
Williams lives with her father and paternal grandmother, and investigators are searching for her mother, Schylon Stewart, 21, who told other family members that she has the child and that she is safe, according to French.
"Right now we're investigating this as a kidnapping because it wasn't the mother who took her and we need to verify that the mother has the child," French said.
Anyone who has information about the whereabouts of Williams or Stewart is asked to call Richmond police at (510) 619-6458.