Trejo was last seen in Las Cruces, New Mexico on April 8, 1986. He was involved in gang activity at the time of his disappearance and was on juvenile probation. On the day of his disappearance, his family took him to see his probation officer on Solano Drive, south of Apodaca Park. Afterwards, Trejo asked his mother to drop him off at a friend's home at Dona Ana Apartments. Trejo's mother expected him to return to their own residence in the 1400 block of north Tornillo Street that evening, but he never did. When questioned by police, Trejo's friend stated the two of them had gone to Apodaca Park off Madrid Avenue and Trejo went to the toilets at approximately 2:30 p.m. and didn't come back. He has never been heard from again.

Trejo was having disagreements with rival gang members at the time of his disappearance. After he vanished, unidentified individuals called his family to say he had been murdered. His mother suspects his friends knew more about his disappearance than they disclosed. Trejo had three close friends in 1986 and only one is still alive. One of his friends committed suicide after his disappearance, another was murdered and the third moved away.

Trejo formerly attended Sierra Middle School. Foul play is suspected in Trejo's disappearance, but little evidence is available in his case. His family still lives in the area and still hope for resolution in his disappearance.