LAS VEGAS (AP) -- Investigators interviewed a 6-year-old boy about his nearly four days in captivity in hopes of gaining clues to the identity of gunmen who abducted him last week, police said Monday. The boy, Cole Puffinburger, was dropped off unharmed Saturday night. Authorities think his kidnappers are still in southern Nevada, said Sgt. John Loretto, a Las Vegas police spokesman.
"We believe the suspects are still here, as evidenced by someone dropping him off on that street," Loretto said.
Loretto said police were using Cole's recollections about his captivity to develop leads in the hunt for two gunmen who posed as police officers, bound his mother and her boyfriend, and kidnapped Cole Wednesday morning.
Police have described the boy's abductors as Mexican nationals involved in a methamphetamine ring, and say a third man also was involved.
Meanwhile, Loretto said federal authorities were investigating the boy's maternal grandfather's alleged ties to the drug dealers.
The grandfather, Clemens Fred Tinnemeyer, 51, was due Monday afternoon in a federal court in Riverside, Calif., following his arrest there Friday as a material witness in the kidnapping case.
Police said they believe the kidnapping at gunpoint may have been a message to Tinnemeyer, 51, who authorities say may have stolen millions from drug dealers.
Las Vegas police didn't know whether Tinnemeyer had a lawyer. Police have declined to elaborate on what role he played in the drug operation or whether the kidnappers had been seeking a ransom.
Messages left at a number believed to be for the Tinnemeyer home in Las Vegas were not returned.
FBI spokesman David Staretz said authorities continued the search for another "person of interest," a Mexican citizen identified as Jesus Gastelum.
Gastelum, who is in his mid-30s, is believed to be in Las Vegas or Southern California, police said. Another "person of interest" in police custody Saturday was not identified.
Cole was set free Saturday night on a quiet Las Vegas street outside a Methodist church and was found by a passing bus driver.
He was in "extremely good condition" but was taken to University Medical Center as a precaution. He was treated and released to his father's care, hospital spokesman Rick Plummer said.
Cole's father, Robert Puffinburger, was a picture of relief at a news conference, as he smiled, cried and thanked police and neighbors for helping to bring Cole home.
"I'm just so glad he's safe," his father said.
The bus driver, who did not want to be identified, saw him walking alone and pulled over to ask if he was all right.
"Cole approached the bus and asked the driver, 'Can you take me home?'" said Jacob Snow, general manager for the Regional Transportation Commission of Southern Nevada.
The driver took the blond, blue-eyed first-grader onto the bus and contacted police, Snow said. The child said he had been dropped off just a few minutes before.
Cole's father wouldn't comment on Cole's mother or her father, a carpenter who filed for bankruptcy in 2001.