SANTA ANA, Calif. — Authorities say a 19-year-old University of Pennsylvania student whose body was found buried in a shallow grave at a California park had been stabbed more than 20 times. No weapon has been found.

The Orange County Register reports that authorities are investigating whether the killing was an act of rage.

Orange County Undersheriff Don Barnes says 20-year-old Samuel Lincoln Woodward was arrested and taken into custody Friday on suspicion of homicide after DNA evidence linked him to the death of college sophomore Blaze Bernstein.

Bernstein was home visiting his family in Lake Forest during winter break when Woodward picked him up on Jan. 2 and drove with him to several places before winding up at a park.

Barnes says the two knew each other from high school.