Robert Castro, a 54-year-old Hispanic man, was beaten to death with a piece of plywood in a rail yard in Colton, California on July 5, 1997. He was described as a drifter at the time of the killing.

Ángel Maturino Reséndiz, known as the Railroad Killer, is considered the prime suspect in Castro’s murder though he was never officially charged in this case. Reséndiz was active across the United States during the 1990s and was linked by authorities to multiple murders near railroad tracks; at his July 1999 arrest he was suspected in several such slayings. No other arrests or suspects in Castro’s death have been publicly identified and the case remains officially unsolved.

Did anyone who knew Robert Castro or who worked around the Colton rail yards in 1997 see anything that could help investigators?