ST. JOHNS COUNTY, Fla. -

The mother of a 23-year-old college student struck by a pickup truck and killed while riding his bicycle in St. Johns County earlier this month is pleading for the public's help in finding the person responsible for her son's death.

The family of Bryan Wrigley, of West Columbia, S.C., has raised the reward from $1,000 to $5,000 for information leading to an arrest.

Wrigley, who was a student at the University of St. Augustine, was found dead in a ditch on the side of County Road 214, near Molasses Junction, on April 13.

"A mother should never have to bury her child," Wrigley's mother, Mandy Wrigley, said in a phone interview Tuesday. "He should have been sitting with us at the dinner table on Easter. My family is destroyed. My family is destroyed."

It's been nearly two weeks since the crash, and investigators are still looking for the driver responsible for the hit-and-run.

Investigators were able to put together a composite sketch of the driver from a witness. They describe the driver as a white man possibly in his 20s.

Deputies believe he was driving a dark blue 2001-2003 Ford Ranger pickup truck with extensive front-end damage, including to a fog light. They said the truck had fog lights molded into the front bumper. They also said it is possible the vehicle was leaking fluids and may now be disabled.

Mandy Wrigley said she just wants answers.

"I'm numb. It's like I'm dead inside," she said. "I don't know where to go now. I don't know what to do."

All Mandy Wrigley has now is memories and pictures of her son and his smile that could light up a room.

Bryan Wrigley was seeking his doctorate in physical therapy at the University of St. Augustine. He was a member of a local cycling club and loved helping out with the Special Olympics.

His mother said she's praying the driver will come forward. She knows nothing will bring her son back, but she said her family will find comfort in knowing the person responsible is in custody.

"I just need help," she said. "I want the public's help to just help us find this person responsible so they can't hurt anyone else like they've hurt us."

If you know anyone who has a pickup truck with recent front-end damage or a truck that has been sold or disappeared unexpectedly, call the St. Johns County Sheriff's Office at 904-824-8304 or Crime Stoppers at 888-277-TIPS (8477).