FRESNO, Calif. (AP) — Authorities say a 21-year-old pregnant woman died after she was shot while riding on the back of a motorcycle on a central California freeway.

The California Highway Patrol says Savanna Troyn fell off the bike and was run over by at least one vehicle after the shooting early Saturday on State Route 41 south of Fresno.

The CHP is investigating the case as a homicide, but as of Monday, no information had been released on a possible suspect or motive.

Troyn’s father, James Castro, tells the Fresno Bee that his daughter was 2-1/2 months pregnant with her first child.