The Guadalupe County Sheriff's Office is asking for the public's help in cracking a cold case.
Tuesday marked 15 years that Donna Mumford was hit by a car and left for dead on Timmermann Road in Seguin.
Investigators hope doubling the reward money will entice someone with pertinent information to come forward.
"We're talking about a mom, a wife, a daughter -- one of our citizens that went for a walk and never made it home," said Sgt. Craig Jones.
He’s been working hard on the Mumford cold case for the past five years, and he hopes someone will have new information on her hit-and-run death.
She was killed back in 1998, and leads as to who left her for dead have run cold.
"We do believe somebody knows something so we want to open that door and give every opportunity we can for someone to come forward," said Jones.
Investigators said she was hit by a vehicle while on her routine evening walk on Timmermann Road near Country Road 123.
Mumford was left for dead, and for more than a decade, no one has ever come forward with any new information.
"Whoever struck her didn't stop and may not have even known they hit her," said Jones.
Mumford’s father has donated $5,000, which brings the reward to now $10,000.
Jones remained hopeful the Mumford family will soon get closure on her tragic death.
“It's just not a well-travelled road (and) it's still not today and it wasn't even back then, so somebody knows something," said Jones.