SANTA ANA, Calif. -- A murder charge has been filed against a suspect in the death of a University of Pennsylvania student whose body was found buried and stabbed in a Southern California park. A complaint filed in Orange County Superior Court Wednesday morning alleges 20-year-old Samuel Woodward used a knife to kill 19-year-old Blaze Bernstein.

Orange County prosecutors also filed a so-called enhancement which would allow them to seek more jail time for Woodward if he is convicted.

Authorities say Bernstein was visiting his parents during his college's winter break when he went to a park with Woodward on Jan. 2. His body was found in a shallow grave there a week later. Woodward was arrested soon after.

Blaze Bernstein Orange County Sheriff's Department

In an affidavit obtained by the Orange County Register, Woodward told investigators he was angry after Bernstein kissed him the night they went to a park.

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Bernstein's parents say the killing may have been a hate crime against their gay son.

Orange County District Attorney Tony Rackauckus told reporters Wednesday that investigators are looking for evidence that would support making the legal case a hate crime.

Rackauckus says both had attended the Orange County School of the Arts, but couldn't speak to whether they were friends. The district attorney says Woodward communicated with Bernstein by Snapchat on Jan. 2 and then picked him up at his parents' house.

Rackauckus said Woodward had been under surveillance before his arrest. He alleged Woodward visited the crime scene days after the murder happened, but wouldn't provide more details.

Rackauckus also said Woodward cleaned his car and that Bernstein's DNA was found "on property that was in control of the defendant."

Bernstein's family is devastated, Rackauckus said.

"This is a senseless murder of a young man who possessed a combination of high caliber mind and the heart of a poet," Rackauckus said. "I know he was treasured by his family and loved by his friends."

He said his office's priority is to bring Woodward to justice.