Courtesy Photo Robbie Smith appears in this photo provided by the Michigan State Police.

Police believe a Lewiston man threatened to post nude photos of a minor to force her into a relationship, the Michigan State Police said on Monday.

In May, a Lewiston-area mother reported that Robbie Smith, then 21, had harassed her daughter via social media and demanded the girl resume a relationship with him, threatening to share nude photos of her if she did not comply, according to police.

When officers seized Smith’s cell phone, they found numerous sexually explicit images of women, along with photos of the minor, police said.

When local police contacted officers in Washington state, where Smith was staying at the time, requesting extradition, Washington police learned Smith had returned to Michigan, according to police.

On Friday, Smith turned himself in at the Oscoda County Sheriff’s Office. He was charged with possession of child pornography and using a computer to commit a crime.