Authorities said the party was held in a home on Lancelot Lane. He had reportedly been in a disagreement with his girlfriend and brother about O'Connell's decision to join the ROTC program at Lafayette College. O'Connell left on foot.
His family reported him missing after he failed to return home that night.
Authorities said O'Connell was struck and killed while walking north of Getty Center Drive on the 405 Freeway at 2:30 a.m. Saturday. Fingerprints confirmed his identity.
Authorities told the family two times on Sunday that the body found on the 405 was not O'Connell.
The 20-year-old attended Lafayette College in Pennsylvania, and he went to school with the daughter of Gov. /*Arnold Schwarzenegger*/ and /*Maria Shriver*/. The Schwarzeneggers have reportedly reached out to O'Connell's parents.
Anyone with information related to the incident is urged to call (213) 996-1800.