( CNN ) -- DNA test results reveal that a Michigan man is not a Long Island , New York , boy who went missing 54 years ago , according to the FBI . John Robert Barnes claims a DNA test shows he 's Steven Damman , who vanished in 1955 . John Robert Barnes , of Kalkaska , Michigan , approached police in New York twice in March claiming to be Steven Damman , a toddler who vanished while on a shopping trip with his mother in 1955 . Barnes tracked down Pamela Damman Horne , Steven 's sister , and the two had private tests performed that showed a `` probability '' they were siblings , according to Nassau County , New York , detective Lt. Kevin Smith . But samples from Barnes and Horne analyzed by the FBI Laboratory in Quantico , Virginia , determined that they do not share the same mother , the FBI in Detroit said Thursday . Sandra Berchtold , spokeswoman for the FBI Detroit bureau , said the FBI follows strict testing protocols and used mitochondrial DNA to determine Barnes and Horne were not linked to the same mother . Marilyn Damman took her toddler , Steven , and his baby sister , Pamela , to a food market in East Meadow , Long Island , in 1955 . The mother went inside to do some quick shopping , leaving her 2-year-old son and baby girl in the stroller outside . But Damman told authorities that when she returned , her children were gone . A short time later , blocks away , the baby girl was found unharmed and the stroller was intact , but Steven was missing , Smith said . CNN 's Stacey Newman contributed to this report .
John Barnes claimed he was Steven Damman , who went missing 54 years ago . He said that his parents had been murdered and the police were covering it up. Steven went missing in East Meadow , Long Island , in 1955 .