SAN DIEGO -- Authorities announced an increased reward of $20,000 Tuesday for information that helps solve the mysterious death of a young Orange County man who disappeared during a night out in the Gaslamp District and turned up dead in a City Heights alley three days later.

The skate and surfwear clothing company that 23-year-old Dane Williams worked for at the time of his death five months ago, Hurley International of Costa Mesa, recently doubled the reward fund by posting an additional $10,000, according to police.

Notices seeking tips in the case have been posted on 45 bus shelters in San Diego and Orange counties.

Williams, a Huntington Beach resident, went missing in the early morning hours of Jan. 26 while on a trip to San Diego to work a convention.

Three days later, a passer-by found the marketing intern's blanket-wrapped body on an access road off the 5200 block of Landis Street, about six miles from the site of his last known whereabouts.

An autopsy and follow-up toxicology tests were inconclusive, and the cause of death has been officially classified as "undetermined." Barring any further information in the case, that ruling will stand as final, according to the county Medical Examiner's Office.

Authorities asked anyone with information about the suspicious death to call San Diego County Crime Stoppers at 888-580-8477. Tipsters may remain anonymous.