Police in Ohio have expanded their search for a boy who disappeared more than a week ago on his way to school.

Harley Dilly, 14, was last seen Dec. 20 in Port Clinton, according to Facebook posts from local police. Surveillance video reviewed by police appears to last show Harley somewhere on his route from his home to the Port Clinton high school and middle school campus between 6 and 7 a.m. on Dec. 20. He was reported missing late Dec. 21.

Harley Dilly in an undated photo. Port Clinton police via Ohio Attorney General's Office

The FBI, the U.S. Marshals Service and the National Center for Missing and Exploited Children are among the agencies that have joined the investigation, police said in a statement Friday.

An extensive search for Harley in the Port Clinton area was conducted on Dec. 22. An additional search that covered more than 150 acres and included about 75 law enforcement agencies, as well as helicopter and K-9 teams, was conducted on Thursday.

Authorities say that they are "concerned for his safety" but that the investigation did not indicate foul play.

"We understand this is a 14 year old child and are exhausting every effort to locate Harley and reunite him with his family," the police department said on their Facebook page.

Harley's family thanked everyone involved in the investigation for their work and begged for his safe return in a statement posted Friday on the police department's Facebook page.

"We want to thank all the agencies and all the people from the community who have assisted in searching for our son Harley from now and through the holiday season," the statement said. "As you can imagine our family is terribly distraught at this time. This is not the Christmas wish we had hoped for. We pray for the safe return of our son, Harley. Harley if you hear/read this, please come home we missed you, your family miss you. You are not in trouble. We love you."

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Police were sent to Harley's home last month to calm him down after a "family issue" occurred, according to NBC affiliate WNWO of Toledo.

Police Chief Rob Hickman asked residents on Friday to go door to door and pass out Harley's missing persons flyer. Police are offering a $7,000 reward for information leading to his safe return.

Harley was last seen wearing glasses, gray sweatpants, a maroon puffer jacket and black tennis shoes. He is 4 feet, 9 inches tall and weighs about 100 pounds. He has brown hair and green eyes.

Anyone with information was asked to call Port Clinton police at (419) 734-3121 or the National Center for Missing and Exploited Children at (800) 843-5678.