The pregnant wife of a man killed by a boulder that crashed through the window of their car near Los Angeles is pleading for information that leads to the arrest of the person responsible for pushing the rock off an overpass.

The California Highway Patrol says someone pushed the 35-pound (16-kilogram), basketball-sized rock off a freeway overpass in Pasadena late Tuesday, sending it smashing through the windshield.

Twenty-three-year-old Christopher Lopez, who was in the passenger seat of the Toyota driven by his wife, was killed.

Guadalupe Gutierrez was unhurt, as was their 4-year-old daughter in the back seat.

Gutierrez fought back tears Thursday as she asked for potential witnesses to come forward.

The highway patrol says investigators believe someone purposefully pushed the boulder into westbound lanes of State Route 134.