SAN DIEGO (NEWS 8) - San Diego Police are asking the public's help in locating a Chula Vista 18-year-old who has been missing for four days. 

According to police, on Sunday July 29th, 2018, Guillermo Gradilla walked out of his residence. He suffers from Autism and epilepsy. 

Maria de los Reyes is Guillermo's aunt and legal guardian. "Everyone is looking for him and we want him to be ok," she said. It is unknown where he could be and Gradilla has a history of running away. He has been known to travel into Mexico and to the Los Angeles area to locate relatives in the past.

On Monday July 30th, 2018, MTS cited Guillermo for fare evasion near 750 E Street, Chula Vista. His aunt said "he likes Spiderman and loves Sprite and chicken nuggets." 

The family said the teen is socialable and touchy and could be mistaken by strangers because he has the mental capacity of a six-year-old. "everybody misses him," said his aunt. Guillermo has a big heart and his family is pleading for any information about his disappearance in hopes of his safe return. 

Guillermo is described as a Hispanic male, 5'-7", 185 LBS, with black hair and brown eyes. 

Any information related to the whereabouts of Gradilla should be forwarded to San Diego Police Department at (619) 531-2000 or SDPD Missing Persons Unit (619) 531-2277.