SAN DIEGO -- As thousands of Southern California teenagers and young adults prepare to head to Mexico for spring break, a North Carolina mother is still trying to find out who killed her son in Tijuana almost one year ago.

Shane Pennington, 19, was living his dream. He was new to California and had his eyes set on joining the Army.

Pennington, however, was found stabbed to death in Playas de Tijuana, and his mother, Elizabeth Taylor, is still dealing with the tragedy.

"It's getting hard again. Still not ever heard nothing … I've had to deal with the birthdays, the holidays. That it's been a year now, it's catching up," said Taylor.

From her North Carolina home, Taylor told 10News there are still so many unanswered questions surrounding her son's death. It remains unclear why Pennington was in Mexico and why someone would kill him.

"There are no answered questions. Still, you know, thank goodness for the detective in San Diego. He is still keeping it active," Taylor said.

Tijuana Deputy Attorney General Salvador Ortiz Morales said Pennington's death was not drug related, but it may have been personal or the result of a robbery.

Mexican authorities said Pennington was stabbed to death with his own knife -- a Christmas gift from his mother.

10News was with Taylor last April as she identified his body at a Tijuana morgue, and she said, "Who … who did this to my son?"

Today, she remains haunted by Pennington's death and wants justice for her son.

"You're unable to rest. It's not finished," said Taylor.