MARTINEZ, Calif. (KRON) — Fred Marion Cain III, the man charged with murdering 6-year-old Jeremy Stoner in Vallejo, is now being investigated by police for a second cold case in Martinez.

Cain, 69, was arrested on September 18 at his Gold Hill, Oregon home and he remained in custody Thursday.

Nine-year-old Eric Coy was riding a bicycle around his Martinez neighborhood when he was kidnapped on Jan. 24, 1987. His body was found the following day in a stream by Martinez Junior High School in Contra Costa County. Eric’s killer stabbed him nearly a dozen times, according to investigators.

Fred Marion Cain III is escorted away in handcuffs on Sept. 18, 2023. (Image via Jackson County Sheriff’s Office).

Jeremy, 6, was playing with his brothers in their Vallejo neighborhood before he was kidnapped, sodomized, and brutally slain on Feb. 21, 1987. A four-day-long search effort in Solano County ended when Jeremy’s body was found on Sherman Island in Sacramento County. Like Eric, Jeremy had also been stabbed.

 Jeremy Stoner
Jeremy Stoner was six years old when he was kidnapped and killed.

The boys were kidnapped and slain within weeks of each other, and for 36 years, their killer’s identity remained a chilling mystery.

Advances in DNA technology linked Cain to Jeremy’s death, Solano County prosecutors announced this month.

This week, another major new development surfaced. Martinez police Lt. Patrick Salamid told KRON4 that Cain is now considered a “person of interest” for Eric’s death. Citing legal reasons, Salamid would not go as far calling Cain a “suspect” in the Eric Coy case.

Eric Coy
Eric Coy was killed when he was nine years old. (Image via Martinez PD)

“Cold case homicides never go away — especially one when it involves a child,” Salamid told KRON4. “We’re not going to forget the death of Eric Coy, and we’re gonna keep investigating this case until we find a solution to this case. Mr. Cain is a person of interest.”

Cain was extradited back to Solano County on Wednesday to face charges for Jeremy’s death. He is charged with murder, including special circumstance allegations of kidnapping and sodomy.

Fred Marion Cain III
Fred Marion Cain III

District Attorney Krishna Abrams said, “I am so thankful to have such dedicated cold case investigators, that no matter how much time goes by, they remain steadfast in their commitment to solving these horrific cases.”

The accused killer made his first court appearance on Thursday and did not enter a plea. Cain’s next court appearance is scheduled on October 12 for arraignment.