WINFIELD, Ala. (AP) — Authorities in Alabama are searching for a missing 1-year-old boy who was last seen in September but whose disappearance did not come to light until his parents were in a deadly car crash this month.

The Alabama Law Enforcement Agency issued an emergency missing child alert Tuesday for Kahleb Collins. Law enforcement officials used dogs to help search the family’s home and property in Fayette County on Thursday, WBMA reported.

The child’s disappearance came to the attention of authorities after a deadly Dec. 8 car crash that claimed the lives of his father, Steven Bradley “Brad” Collins, as well as 2-year-old sibling, Ryleigh Collins, and critically injured his mother, Wendy Bailey. The Fayette County Sheriff’s Office said Monday they learned while investigating that the couple had another child, the 1-year-old, who “was unaccounted for.”

Investigators made a public appeal for information about the child. The state law enforcement agency said Tuesday that the boy was last seen Sept. 4.

“This case has been the top priority of all agencies involved since a vehicle crash brought his disappearance to our attention 11 days ago,” District Attorney Andrew Hamlin said in a statement to news outlets.

He said they expect to be able to release more information in the coming days. He asked people to be cautious about unverified information about the case circulating on social media.

Court documents show the investigators believe the boy may have been harmed.

Authorities charged the boy's grandfather, John Bailey, with failing to report a missing child. Law enforcement officials wrote in the complaint that no report was made “with willful and reckless disregard for the safety of the child and the child suffered serious bodily harm or death.”

James Standridge, a defense attorney representing Bailey, said they are working to learn more information.

“All I can say is we are undergoing an investigation," Standridge said. “We expect to learn more.”

Court records associated with the case show that prosecutors are seeking information from child welfare authorities on if there were any complaints involving the family.

A Nov. 6 Facebook post by Brad Collins said his son was having health issues and would need to have surgery at some point. He asked that people keep the boy in their prayers and said the family had a “long tough road ahead of us.” The Associated Press could not verify who made the post.