Police arrested the Newton Free Library employee at his home after Massachusetts State Police detectives linked his computer to a file-sharing program that allegedly distributed child pornography, according to the press release.

“These are very troubling allegations, where a city employee working in a public library was in possession of child pornography,” said Middlesex D.A. Gerry Leone  in the press release. “Children are our most vulnerable victims and we will continue to prosecute those who harm or exploit them.”

Buchanan did not have a criminal record, according to the Newton Police Department. The Newton Free Library, which performs background checks on potential employees, did not find anything questionable in his past.

At the arraignment, Newton District Court Judge Dyanne Klein ordered that Buchanan be held on $5,000 cash bail, on the condition that he does not come into contact with children under the age of 18, use any computers or visit Newton’s public libraries.

The arrest comes after an investigation led by Bay State detectives from the Massachusetts Internet Crimes Against Children Task Force, which worked in conjunction with the D.A. office’s Cyber Protection Program.

The CPP, according to a press release, focuses on “the protection of children and other citizens from the predatory dangers of the Internet.”

Buchanan’s case is not related to the arrest made last Tuesday of a Newton schoolteacher who was also charged with possessing child pornography, according to the NPD.

Police arrested David Ettlinger, a 34-year-old Brighton resident, at his home on Commonwealth Avenue last week. Before his arrest and arraignment on Jan. 18, Ettlinger taught second grade at Underwood Elementary School after working for Newton’s school system for 12 years.

Police found images of minors in sexual contexts on Ettlinger’s computer.

At Buchanan’s arraignment Wednesday, the court scheduled a pretrial conference for Feb. 13.