Santa Cruz police arrested three people Thursday after responding to a report of illegal drug activity in the Pogonip Open Space Preserve near the city. Alfonso Marquez, 23, Rey Antonio, 23, and John Pitts 31, were all arrested after officers arrived in the preserve at about 10:30 a.m. Thursday, according to police. Officers spotted the three men, all transient Santa Cruz residents, and found Marquez and Antonio to be in possession of illegal narcotics for sale, police said. Marquez was arrested on suspicion of possession of more than 10 grams of heroin for sale, loitering in a place were narcotics are used or sold, and for being under the influence of a controlled substance. Antonio was arrested on suspicion of possession of methamphetamine and marijuana for sale, and was also in violation of his probation terms. Pitts was arrested for outstanding narcotics-related warrants, according to police. Anyone with information about illegal activity is asked to call the Santa Cruz police tip line at (831) 420-5995.