A San Jose man accused of killing two people in separate attacks may be a serial killer, authorities warned, saying there could be more victims.
Marcelino Castro, 28, has been charged with two counts of murder after he allegedly confessed to killing two men and led police to their bodies in different locations along the Guadalupe River.
“Although there’s only two victims, it looks like the start of a possible serial killer case, and I’m grateful he turned himself in before he continued,” Deputy Santa Clara County District Attorney Michael Gadeberg told SFGATE Thursday.
Castro “flagged down” a San Jose police officer on September 19 and told authorities he had killed someone near Lelong Street and West Alma Avenue, police said in a news release. He then led officers to a body buried near the Guadalupe River by Tamien Station, according to a police report obtained by the outlet.
After officers found the first victim, Castro confessed to a second killing and led investigators to another body near the Guadalupe River Trail by Coleman Avenue and Autumn Parkway. The victim had been wrapped in a red tent and left in tall grass near the river, according to a police report obtained by SFGate.
Authorities believe the first killing occurred September 13, while the second happened either September 15 or 16, Gadeberg said.
Neither victim has been publicly identified.
According to the police report, Castro told officers he knew the first victim and had gone with him to an area near Tamien Station to smoke methamphetamine. Castro allegedly attacked the man “without provocation,” strangling him and slitting his throat before digging a shallow grave and burying him.
Days later, Castro allegedly targeted a second man. He “lured” the man to an area near the Guadalupe River Trail by offering to smoke with him, prosecutors allege.
Castro allegedly strangled the man and hit him with a rock before wrapping his body in the red tent and leaving it in the tall grass.
“It appears that this man may have just had a compulsion to kill and he started with someone he knew and then progressed to a random stranger,” Gadeberg said.
Gadeberg said the second victim was found in an area frequented by runners, families visiting a nearby playground and people living in homeless encampments. He said the victims may have been unhoused, but that has not been confirmed.
“Those areas are frequented by homeless people, but our understanding is that the defendant lured them to those locations,” he said.
A motive for the killings has not been identified. Gadeberg said the case is unlike anything he has previously encountered.
“I’ve never seen anything like this. I’ve had a spree killer case and a number of double homicides, but I have never had something like this where there is no apparent connection or motive,” Gadeberg said.
The two killings are San Jose’s 20th and 21st homicides of 2026, police said in the news release.
