LAS VEGAS -- Another arrest has been made in connection with the kidnapping of 6-year-old Cole Puffinburger.

Jose Lopez-Buelna, 48, was taken into police custody while officers were serving a search warrant to a Las Vegas residence.

Lopez-Buelna is being held in connection with possession of firearm by a prohibited person. Police did not say how he is connected to Puffinburger's kidnapping.

According to their preliminary investigation, Cole was kidnapped after his grandfather, 51-year-old Clemons Tinnemeyer, stole $8 million in drug money from a Mexican cartel, Metro police said.

After the kidnapping, Metro police named Tinnemeyer as a person of interest in the investigation. Some of the money Tinnemeyer allegedly took has been obtained since Tinnemeyer's arrest, Metro police said.

Cole was found late Saturday night at a downtown bus stop.

Tinnemeyer and his girlfriend, Terri Leavy, are being held on material witness warrants in San Bernardino County, Calif. He and Leavy will be in court this week to face extradition charges, while a third person of interest is being sought.

Jesus Gastelum, who is in his mid-30s, is wanted for questioning in connection with the kidnapping. Gastelum is about 5 feet 9 inches tall and 185 pounds. Police said he has ties to the cartel and Tinnemeyer's family.

The boy's mother is now being investigated for her potential ties to the cartel, Metro police said. They have not said if she would face any charges.

Cole's abductors are described as having Hispanic accents. One man is described as in his early 30s, 5 feet 7 inches tall and 150 pounds. He has black, shoulder-length, slicked-back hair. He was last seen wearing a white T-shirt and blue jeans, Rivera said.

Anyone with information is asked to call Metro police at 702-828-3111 or Crime Stoppers at 702-385-5555.