(KTVU) Fremont - It was the middle of the night on a Sunday when Maria Hernandez got up to go to work. She usually got a ride from her boyfriend, but for whatever reason, he couldn't take her.
So instead, she decided to walk to from her home in Newark, to her job at a Fremont nursing care center, about four miles away.
"Her daughter Carmen was like, 'No, Mom, I don't want you doing that. I'll walk with you,' " said Fremont police Detective Jacob Blass.
But it was cold and chilly. As they were halfway there, they decided to call for a ride.
It was about 3 in the morning on Feb. 1, 2004 when Carmen's cousin Helidee Cuellar got that call.
"Carmen called me to give my aunt a ride," Cuellar said.
But as the two women walked along Thornton Avenue in Fremont, someone began following them. The person then chased them to the corner of Alameda Drive and contra Costa Avenue, in a neighborhood filled with freshly-pruned trees.
Carmen's cousin was on her way in her car.
"On the way there, I tried to call her and I heard her screaming," Cuellar said.
Neighbor Jermaine Shaffer heard screams too and walked outside.. And what he saw horrified him.
"And that's when I saw the guy standing there and hitting the women in the head with some sort of object," Shaffer said.
That object turned out to be a tree branch that had been left in a pile on the street.
"And it was big. It was thick. It was like a one-inch tree branch. And it was about this long. So he's going like this on the tops of their heads," said Shaffer, moving his hands up and down.
Shaffer said he yelled "Hey" at the man and threw rocks at him to get him to stop. The attacker threw the tree branch on top of the victims and ran off. Three people in a car parked nearby sped off in another direction.
"Once they fell to the ground, the car drove off and then the guy took off running toward Thornton Avenue," Shaffer said.
Another neighbor Dick Wise ran to the women as they lay on the ground.
"I was down like this," Wise said, with one knee on the ground. "And the bodies were like here and here. So I was like this close to one of them, to the bodies. I don't remember, I don't know which one it was. But there was no chest movement. No sound."
The double murder sent shockwaves through the city. This just doesn't happen in Fremont. On average, the Police Department investigates two to three homicides a year.
Maria Hernandez came from a small, central Mexico farming town. She believed Alameda County would be a safe place to raise her family. Her daughter had only been in the country for eight months and worked at a Carl's Jr.
Fourteen years have now passed with no arrests, no motive and no justice
"I hope that someone just sees this and goes, 'I need to come forward, because these girls need some peace. These family members need some peace,' " said Detective Blass.
Blass, a cold-case investigator, says he believes the killer knew the victims.
"And it takes a lot of hate, and that's why it's almost like more of a crime of passion to me," Blass said. "Someone said, 'Hey I'm taking out my anger on you because of x, y, z.' Why? I don't know. I mean was there a connection? I believe so."
And the murder weapon - a tree branch the killer happened to find on the street
"This particular one, it's so up close and personal, where this person was, 'I'm literally going to grab whatever I can find, and my intent is to kill these two people,' " Blass said.
Police have looked at the mother's boyfriend, acquaintances and checked out their alibis.
"We've had leads through the years, sending us different pathways to where we're going, and it just, each one's hit a dead end," Blass said.
Police do have some leads, including a sketch of the attacker.
And the car that sped off after the slayings it was an '80s Honda Accord As it left, the car's headlights flipped up in the dark.
And perhaps the most tantalizing clue yet: police found DNA from the tree branch, but don't know who it belongs to.
"So that leaves me to believe that that person committed the crime and then fled somewhere, or - and never committed another crime," Blass said.
The violence left loved ones wondering why. Why would someone kill a mother and daughter?
"It's very sad. I don't know why they do that to her," Veronica Palacios, a friend of Carmen Hernandez, told KTVU in 2004. "She didn't have no enemies, not that I know."
Fremont police are asking anyone with information to text 'Tip FremontPD' followed by msg to 888-777 or send an anonymous tip online to https://local.nixle.com/tip/alert/6157639