Transcript for Manhunt underway after rock kills a young mom
We move to a manhunt in Texas after someone threw a rock from a highway overpass that killed a young mother riding in a car below with her children Marcus Moore is at that you spoke to her boyfriend who was driving the car. Reporter: That's right. He says they were in the far right lane of the interstraight just behind me together as a family when all of a sudden he heard a loud and horrible sound. Advise, she was hit by a brick. Looks like someone threw a brick off the overpass. Reporter: Police in Texas are hunting for the person who killed Keila flores, she was riding in a car with her boyfriend when someone through a large rock from an overpass. It was a loud impact. Almost like an explosion that went off in the car. I didn't know what it was. Reporter: Her family watching in horror as she sat badly injured from that startling and lethal blow. It happened around 8:40 Saturday night along this stretch of interstate 35 in central Texas as the family drove home from an evening out. With few clues investigators are now urging the public for help. We're asking people if they have any information, any surveillance videos to contact the temple police department. Reporter: This kinds of incidents happening with terrifying frequency. A Tennessee man driving to work when a slab of concrete crashed through his windshield killing him. That still unsolved. Last last year -- I just went underneath the bridge and something hit my car. Reporter: A six-pound stone took a young father's life. Now this morning here in Texas, the family of Keila flores mourns her senseless death and hopes for justice. She didn't deserve that and no one deserves that, an innocent person, good mother, good sister, to do that, senseless. Reporter: And none of it makes any sense. Rodriguez performed cpr on his own girlfriend to try to save her life but it was not enough. A good samaritan also tried to help and Rodriguez's grateful for that person and this morning, he is hoping for a break in this case. Guys. Such a horrible story. What a senseless death. The reality show shocker.
This transcript has been automatically generated and may not be 100% accurate.