Updated at 9:36 a.m. to reflect that the boy died.

A 5-year-old boy died Wednesday night, days after he was found with a slashed throat following a suspicious Plano apartment fire that investigators suspect his mother intentionally set, according to court documents.

The mother, identified as 30-year-old Santhiya Lakshmigari, had severe burns and died at an area hospital after Monday's fire.

Her young son, identified as Mounesh Lakshmigari, was taken to Parkland Memorial Hospital, where he died two days later.

Fire investigators determined that the fire was started in multiple spots around the apartment. They suspect Santhiya Lakshmigari started the blaze and attempted to kill her child, according to a search warrant.

A firefighter at the scene said the boy was found in the kitchen in a pool of blood. The boy had a some kind of cloth wrapped around his neck, his throat had been cut and his skull fractured, according to court documents.

A knife was found at the scene under a bottle of cooking oil.

The fire started about 4:40 p.m. Monday at the Villas of Preston Creek apartments in the 6900 block of Preston Road, near Legacy Drive.

A neighbor told authorities she'd seen Santhiya Lakshmigari talking and screaming at herself and ignoring her child, according to a search warrant.

The case remains under investigation, and police have released few other details.

Breaking News Producer Liz Farmer contributed to this report.