Updated

A 9-year-old boy originally from Russia who was killed in a Nebraska house fire has been laid to rest, but prosecutors and the Russian government are seeking more information about his death.

Nearly 200 people gathered at a Lincoln church Wednesday to mourn the death of Anton Fomin. He was living with legal guardians when he died May 17 in the fire. He was home alone in Davey, Neb.

Anton immigrated to the U.S. with his biological parents, but court records show he hadn't lived with them since 2005.

Anton's father died of cancer in 2008. Court records say his mother was unable to care for him.

Russia has long demanded the U.S. tighten controls over adoptions from that country, and a Russian official raised questions about Anton's death.

Anton's legal guardian, Slavik Sinchuk, who refers to himself as the boy's stepfather, said earlier media reports about the boy being locked in a basement were untrue.

Sinchuk and the boy's church youth pastor, Oleg Stepanyuk, said Anton was asleep before the fire started. They said Sinchuk and his wife went briefly to visit Sinchuk's father in Lincoln and didn't want to disturb the boy, so they left him asleep in his basement bedroom.

They returned 30 to 45 minutes later to discover the house in flames. Sinchuk said he didn't know how the fire started, but he said neighbors reported hearing an explosion shortly before the blaze.

Relatives and friends of the boy said Anton had bounced among families after his father's death, but had grown to love Sinchuk and his family.

The church pastor, Bogden Stebanyek, said Anton's mother suffered from mental health problems. He said Anton's father, who was dying of cancer, requested that he be placed in the care of another family that could care for him.

"His wife couldn't take care of Anton," Stebanyek said through a translator.

He said the church tried to connect the boy with a member family that had children his age. One family took in Anton's older brother, who is now 20, and Anton went to a family with four other children.