LAKEWOOD, Wash. -- Lakewood police investigating the death of Adre'Anna Jackson have learned the results of forensic tests on items belonging to Therpon Adhahn, a sex offender who is a person of interest in the case and who is accused of killing a 12-year-old Tacoma girl, KIRO 7 Eyewitness News reported.

Police said they will not comment on whether the tests found a link between Adre'Anna's killing and Adhahn.

Adre'Anna, 10, was last seen alive when she left for school Dec. 2, 2005. Two boys playing in a field found her remains four months later. The Pierce County medical examiner was not able to determine a cause of death, but ruled it a homicide.

VIDEO: Investigators Tight-Lipped About Crime Lab Results

Zina disappeared from an alley behind her home in Tacoma on July 4, 2007, during a fireworks display. Her father heard her scream and saw a gray van driving away. His description of the license plate led authorities to Adhahn, a 42-year-old Thai immigrant who was convicted of incest in 1990 for raping his 16-year-old half sister.

Adhahn was charged with aggravated first-degree murder, first-degree kidnapping and first-degree rape in Linnik’s death. Prosecutors said he agreed to lead police to Linnik’s body in a deal to avoid facing the death penalty.