Authorities in Illinois were searching Sunday for a missing 5-year-old boy, Andrew Freund, who appeared to have vanished from his family’s home last week.

After investigators in the suburban Chicago city of Crystal Lake unsuccessfully scoured hundreds of acres and searched the city's lake for traces of Freund on Thursday, the local police department said in a statement that he had not been abducted and it did not appear that he walked away from his home.

No suspects have been identified in the boy’s disappearance, though the department said “information obtained currently has police focusing on the residence.”

Andrew Freund, Jr., 5, went missing from his home in Crystal Lake, Illinois. Crystal Lake Police Department

Andrew’s parents told authorities they last saw him at roughly 9 p.m. local time on April 17, police said.

When the parents were unable to find the boy at home the next morning, they called police, the statement said.

Authorities then searched nearly 1,000 acres by foot and with drones, while sonar and underwater cameras were used to scan Crystal Lake, the department said.

When a canine team examined the family’s home, police said, they “picked up Andrew’s ‘scent’... indicating that Andrew had not walked away on foot.”

Andrew Freund, Sr., the father of the missing 5-year-old, walks near his home in Crystal Lake, Illinois, on April 19, 2019. John Starks / Daily Herald via AP

NBC Chicago reported that the boy’s father, Andrew Freund Sr., was seen getting into a car with investigators after they obtained a search warrant for the family's home.

He declined to speak to reporters, though on Sunday he told NBC Chicago that he had “no control over what people think. I just want my son to come home, okay?”

A lawyer for the boy’s mother, Joann Cunningham, told reporters Friday that she had “cooperated extensively with police until at some point we got the impression that she may be considered a suspect,” the Chicago Sun-Times reported.

“I don’t know whether she is or not and I don’t know how serious that consideration is,” said the lawyer, George Kililis, according to the newspaper. Kililis told NBC News that Cunningham is seven months pregnant and "emotionally and physically exhausted."

NBC Chicago reported that Andrew had been in foster care for two years after he was born with opiates in his system, and his parents were twice investigated last year over unsubstantiated neglect and abuse allegations.

The state Department of Children and Family Services took the boy’s younger brother into custody on Friday, the station reported. It was not immediately clear why.