Parents of Missing Special-Needs Toddler Have 'Stopped Cooperating' with Investigation: Police

"We are hopeful that they will resume cooperating and help us to locate Thaddeus," cops said in a statement

Police in California say that the parents of a missing 2-year-old boy with special needs have "stopped cooperating" in the investigation to find him.

Thaddeus Sran vanished from his Fresno home in the middle of the night. In a press conference last week, Madera Police Chief Dino Lawson said the child's parents claimed to have put Thaddeus to bed at 10 p.m. on July 14. When they checked on him at 8:30 a.m. the next morning, they said he was gone.

At the time, Lawson called the disappearance "a parent's worst nightmare."

But in a new statement, authorities allege that Thaddeus's parents have not aided in the search for their missing son.

"Unfortunately, Thaddeus’ parents stopped cooperating early on in the investigation," the statement reads. "We believe their assistance in this case would be helpful. We are hopeful that they will resume cooperating with Madera Police Department detectives and help us to locate Thaddeus."

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Authorities have been searching surrounding areas for the boy, who was born prematurely and has "extreme health issues."

According to Lawson, Thaddeus uses a feeding tube and was just learning to walk, but crawls to get around. He is also nonverbal. Authorities are investigating Thaddeus' disappearance as a possible abduction.

"Everything is on the table and we’re not ruling anything out,” Lawson said, adding that the Madera County Sheriff’s Office, US Marshalls and FBI are aiding in the search and investigation.

In an interview with ABC30, Madera Police Lt. Josiah Arnold confirmed that Thaddeus' parents had another daughter who died in Madera a few years ago. He gave no further details.

The toddler's parents have not yet spoken out, nor have they been accused of any crime at this time. It is unclear if they have an attorney, and they have not returned PEOPLE's message for comment.

Thaddeus was last seen wearing a red shirt and Spiderman pants with a diaper underneath. He is about 2 feet tall and 30 lbs. His family is offering a $5,000 award for information that helps find their son.

"At this point, the most critical thing members of the public can do is to call if they have any information related to this case," the Madera Police Department said in a statement.

The department phone number is 559-675-4220.

Updated by Steve Helling