A 16-year-old boy arrested for allegedly fatally stabbing a 17-year-old boy with whom he had been in a romantic relationship and then joining a search party and 'finding' the victim's body in an apparent effort to fool investigators appeared in juvenile court in Pomona Monday.

His arraignment was postponed to May 10, according to a spokeswoman for the Los Angeles County District Attorney's Office, who said no information about the case against him filed on Friday could be disclosed until after arraignment.

Investigators with the Los Angeles County Sheriff's Department arrested the boy, who they said was a friend of Jeremy Sanchez, Thursday morning after serving a warrant at the suspect's home, sheriff's Lt. John Corina said. Corina later confirmed an NBC4 report that the two boys had been in a romantic relationship and investigators believed the stabbing stemmed from a break-up.

Friends of Sanchez said that he was bisexual and was breaking up with the suspect to date a girl, which enraged the suspect.

The suspect, whose name was withheld, was booked on suspicion of murder and was at least initially held at Los Padrinos Juvenile Detention Center, Corina said. Authorities said the murder weapon was not recovered from the scene or in the immediate wake of the suspect's arrest. Sanchez's body was found about 4 p.m. Wednesday in the riverbed of the San Gabriel River near South El Monte, authorities said.

Sanchez was a student at South El Monte High School. Extra counselors were on hand at the campus on Thursday. Corina said the boy's father had reported him missing after he didn't show up for school Wednesday.

The father and the boy's friends -- the suspect among them -- went looking for him, Corina said. Authorities initially had reported that the father had found the body.

"Actually, it was the suspect in this case who 'discovered' the body," Corina told reporters. "The suspect joined the father in searching for the victim, and it was the suspect who found the body, and he then called the dad and said, 'Hey, he's over here.' So it's kind of unusual. The suspect went ahead and tried to make it seem like he was trying to help out the investigation."

A friend, Briana Amigon, established a GoFundMe page to support the family.

"Jeremy Sanchez was a loving young man who was outgoing and full of energy," she wrote on the page. "He loved playing sports. He was on the varsity football team and also on the wrestling team. We have no words to describe the grief that their family is experiencing right now, and many friends and family have asked how they can help at this difficult time."

The page is at www.gofundme.com/in-loving-memory-of-jeremy-sanchez. Anyone with information on the case was urged to call the Sheriff's Homicide Bureau at (323) 890-5500.