Elijah Moore and Enrique Rios, both 17, were classmates at Cesar Chavez Community School in Woodland, Calif., and were working at a construction training program when they vanished 25 days apart without a trace, according to the FBI.
"Through this investigation, we have determined Elijah's disappearance is connected to the disappearance of Enrique Rios, and we believe both are suspicious in nature," Woodland Police Chief Dan Bellini said in a statement.
The boys' families have launched a desperate search as they seek answers. But as leads run out, the FBI has stepped in and is now assisting the Yolo County Sheriff's Office and Woodland Police Department in the hunt.
Authorities said Enrique was the first to vanish on Oct. 16.
The Esparto, Calif., teen was last seen about 9 p.m. at his home. Two days later, his mother reported him missing. According to his mother, Lola Rios Gutierrez, Enrique never picked up his last paycheck and didn't take any clothes from home.
She told the Sacramento Bee that he had texted her saying he had fallen asleep at a friend's home and was headed to school, but later said he was under too much pressure. Enrique told her he would be going away but planned to return.
He hasn't used his cellphone since.
"These are characteristics of someone who may have just gone out for a little while and was expecting to come back home a few hours later," she said on Facebook. "Someone out there knows where he is."
The Yolo County Sheriff's Office initially thought Enrique ran away because no evidence of foul play was found. Detectives investigated Enrique's disappearance but "exhausted all leads," Yolo County Sheriff Ed Prieto said in a statement.
Nearly a month later, Elijah vanished.
The Woodland teen was last seen at school. Surveillance video footage showed Elijah cashing his check at California Check Cashing on Nov. 4 in Woodland. His mother reported him missing two days later.
Woodland police said a text message was sent from Elijah's cellphone on Nov. 6, saying he was headed to the Bay Area. That's the last time he sent a text message. Elijah has not used his cellphone and has not accessed his social media accounts since he went missing.
According to police, an alert was issued to law enforcement agencies in the Bay Area, and authorities talked to friends, family, teachers and employees at the check-cashing business.
But no one has seen or heard from him.
Elijah's mother, Alicia Moore, said it's unlike him to disappear and stop talking to his family.
"In this itty bitty, tiny close-knit town, no one is saying anything," she said.
She thinks someone lured Enrique and her son under false pretense.
She said Elijah, who is the youngest of four children, had just turned 17 on Nov. 3, the day before he vanished. Moore said her son is a "momma's boy," who played video games, loved ice cream and brought stray animals home.
"My biggest fear is that I won't find my son," she said.
Anyone with details about the missing teens is urged to call (800) 225-5324, or submit tips to the FBI.
3:35 p.m.: This article was updated with comments from Alicia Moore.