Zinkhan, 57, has been the subject of an international manhunt since April 25, when police said he shot and killed his wife and two men near downtown Athens.
Investigators said the phone, laptop, wallet and passport were among the evidence Zinkhan left in his Jeep Liberty when he apparently intentionally rolled it into a secluded ravine on the Jackson-Clarke county line the same day as the triple slaying.
Authorities found the Jeep Thursday night.
Evidence from the Jeep did not immediately point to where Zinkhan may have fled, but investigators are looking deeper, according to Jim Fullington, special agent in charge of the Georgia Bureau of Investigation's Athens office.
"We have finished documenting all the items, but we have not finished a complete search internally of the items," Fullington said Tuesday. "We are still processing everything to see what it means."
Athens-Clarke police charged the University of Georgia marketing professor with three counts of murder, saying he opened fire at a luncheon at the Athens Community Theater on Grady Avenue and killed his wife, Marie Bruce, 47, and fellow members of the Town & Gown Players, Tom Tanner, 40, and Ben Teague, 63.
Though there apparently had been discord in his marriage, officials aren't sure that Zinkhan planned to shoot Bruce and the two others. The couple had argued during the luncheon moments before Zinkhan walked to his Jeep, returned with two handguns and opened fire.
Police believe Zinkhan may have hidden in heavily wooded private property off Fowler Mill Road where his Jeep was found - located in Western Clarke County, a few miles from his house on Chesterfield Road behind Georgia Square Mall - while deciding what to do next, then fled on foot or in a second vehicle.
Investigators have accounted for all vehicles registered to Zinkhan and there haven't been any calls made on his cell phones since the killings.
The international manhunt for Zinkhan includes the Appalachian Trail, which runs from Georgia to Maine, because Zinkhan liked to hike, as well as in Europe, where he taught part time at a university in the Netherlands and had a plane ticket for a May 2 flight from Atlanta to Amsterdam.