Police say Hunderup attended various functions on the night of Dec. 13 into the morning of Dec. 14.
Officers found Hunderup at 2:30 a.m. and believed he was intoxicated. Officers released him to his family, not realizing he was seriously injured.
His family took him to a doctor where they found head trauma, but it was too late.
The medical examiner determined injuries were consistent with being hit by vehicle.
Police have released security footage of a car they believe may have hit Hunderup. In the video above, dark red vehicle believed to be involved can be seen on 23rd Street.
If you have any information about the car, call Galveston Police at 409-765-3763. Galveston County Crime Stoppers may offer up to $2,000 for information. You can call them at 409-763-TIPS.