Fremont, California - It has been 17-and-a-half years since Maria Hernandez and her daughter Carmen were brutally murdered in 2004. While their murderer is yet to be found, there's still hope for justice.

February 1, 2004, started off like any other day for Maria Hernandez. Working as a nurse at the Fremont Nursing Care Center, she often worked in the middle of the night, opting to get a ride with her boyfriend. On this day, though, she was making the four-mile journey on foot.

Fremont police Detective Jacob Blass told KTVU that Maria's daughter, Carmen, didn't like the idea of her mother walking through the night all by herself, so she decided to join her.

When it got to around 3AM, though, they called Carmen's cousin, Helidee Cuellar, and asked her to pick them up - it was far too cold and chilly outside to make the walk.

Shortly after they got off the phone, someone began following them from Thornton Avenue in Fremont, to the corner of Alameda Drive and Contra Costa Avenue.

"On the way there, I tried to call her and I heard her screaming," Cuellar remembered. And she wasn't the only one! Jermaine Shaffer, who lived in the neighborhood, also heard something going on and walked outside.

"That's when I saw [a] guy standing there and hitting the women in the head with some sort of object." According to Fremont Police, the object later turned out to be a large tree branch.

Shaffer immediately began yelling at the man in panic and threw rocks in order to get him to stop. It was then that the attacker dropped the branch on top of his victims and ran off northbound on Contra Costa Ave, as another car sped away. Maria and Carmen Hernandez died at the scene.

Cold case investigator Blass says that he believes the killer knew his victims, saying that "It takes a lot of hate, and that's why it's almost like more of a crime of passion to me." This theory was made more likely by the fact that the weapon used was a random tree branch.

Police have questioned the Maria Hernandez's boyfriend and acquaintances, and checked their alibis, but as the investigation progressed, each pathway hit a dead end. Yet, there are still some leads.

A sketch of the suspect, who was described as a white or Hispanic male in his mid 20s is one such lead. His estimated height is about 6'0-6'02" and his weight between 180-200 lbs. He is thought to be of medium to heavy build.

His hair was medium length and brown, and he was last seen wearing a blue denim jacket with light colored sleeves, stonewashed gray jeans, and white tennis shoes.

Investigators have also found DNA on the tree branch, but to this day, they don't know whom it belongs to. Investigator Blass said "So that leaves me to believe that that person committed the crime and then fled somewhere, or – and never committed another crime."

17 years have now passed, and there is still no justice for Maria and Carmen Hernandez. We know that the vehicle that sped away was a 1980s Honda Accord, but not whether it was involved in the crime.

If you have seen or heard anything – no matter how insignificant the detail may seem – please contact Fremont PD Detective Jacob Blass at 510-790-6963.