SAN MARCOS (FOX 5/KUSI) -- Authorities in San Marcos arrested a man on Thursday after he was allegedly found with a loaded, privately manufactured gun in public. According to a news release from the San Diego County Sheriff's Department, deputies from the San Marcos station responded to a call about a disturbance just after 11 a.m. at Connors Park in the 300 block of West San Marcos Boulevard. Arrest made in fatal shooting of 18-year-old Navy sailor in East Village Upon arrival, deputies learned that a man had gotten into a verbal argument with his girlfriend. They also discovered that the man, identified as 37-year-old Juan Beltran, allegedly had a weapon commonly referred to as a ghost gun in his fanny pack. Authorities also found two glass pipes and a small clear bag with a rock of methamphetamine in the fanny pack, the release stated. A man was found with methamphetamine and a ghost gun. (San Diego County Sheriff's Department) Ghost guns do not have a serial number or other identifiable markings, the department said. Without these markings, it can be difficult for law enforcement agencies to track the weapons to their owner or maker and, in turn, delay investigations and other crime-solving efforts. Beltran was arrested and booked into the Vista Detention Facility on various drug and firearms charges, the department said.