TROY – Two individuals now in their 30s may be the critical pieces to solving a 28-year-old homicide cold case of a 9-year-old girl, city police said Thursday.The city's detective bureau is reviewing the killing of Mei-Ling White, who was missing on July 21, 1989 from her Phelan Court Apartments residence and found dead on July 25, 1989 in a wooded area near the apartments.