(NBC News) – Tonight on “Dateline,” just a few hours after the longest day of the year in 1990, hikers find 21-year-old UCLA student Ron Baker’s body in a Los Angeles area train tunnel. As detectives investigate, they begin to wonder if Ron’s interest in an alternative religion is connected to the murder, but soon discover the suspects are much closer to home.

Here’s a preview of Keith Morrison’s report: 

It was just after the summer solstice.  That longest day of the year, June 24, 1990.

DET. RICK JACKSON: My supervisor– uh, called and said, “Hey, I’ve got an interesting case for you and Frank,” and so Frank and I went directly to the coroner’s office to view the body.

Frank was Detective Frank Garcia, Jackson’s partner

DET. FRANK GARCIA: HE Had multiple stab wounds and his throat was slit.

It was a murder, all right – close up, personal, bloody.

DETECTIVE RICK JACKSON: Whoever did this wanted to make sure that it was done. No one was gonna survive this.

He looked to be in his early 20s but had no ID, so they called him John Doe #135. LA’s 135th unidentified victim of the year.

RICK JACKSON: He had a medallion on. And there were two. One was a pentagram. And there was also one that was just a religious cross.

Meaning … something, possibly.

John Doe 135 had been found by hikers in an old train tunnel, that cuts through the rocky hills in suburban Chatsworth.

DETECTIVE RICK JACKSON: Went up to the tunnel the next day …

KEITH MORRISON: What was it like in there?

DETECTIVE RICK JACKSON: Strange. There’s paintings everywhere. Paintings of words r– involving drugs, LSD, acid.

RET. DET. FRANK GARCIA: We were told that they would do animal sacrifices there.  There was writing on the inside of the tunnel. Things about hell and fear.  There was pentagrams all indicating some kind of occult activity that was taking place in the tunnel.

 “Dateline” will reveal the latest developments in the case, as well as interrogation tapes and police photos from the investigation. Watch tonight on NBC4 at 9 p.m.