A Tennessee man has agreed to plead guilty to charges of stealing money from the charity he created to benefit the people of Newtown, Connecticut, following the December 2012 massacre at the Sandy Hook Elementary School.

Robert Bruce is scheduled to appear in federal court in Hartford, Connecticut, on May 12 for a change of plea hearing.

The Nashville man currently faces six federal wire fraud charges stemming from the alleged misuse of money from the 26.4.26 Foundation. The U.S. Attorney's office confirmed a plea deal had been reached, but said details have not been made public.

Bruce was charged in February 2015, about a year after authorities were contacted by Ryan Graney, a co-founder of the charity. She told them Bruce had failed to account for about $73,000 of the $103,000 they had raised.

The idea behind the foundation was for runners to participate in marathons, raising money for each of the 26 miles they ran and dedicating each mile to one of the 26 victims of the shooting -- 20 children and six educators.

The charity held its first marathon in Nashville a week after the shooting, with more than 1,000 participants raising $30,000. Another was held in New Hampshire in 2013. More than 1,400 runners raised about $22,000 for the foundation, organizers said. The charity also received donations from runners in other events, Graney said.

Bruce later presented a $30,000 check to a youth sports center in Newtown.

Graney said she noticed something was amiss, when she discovered suspicious charges to the foundation's PayPal account, including $1,200 billed for paddleboards. She said she later found a picture of a new paddleboard on Bruce's Instagram page.

Graney said she confronted Bruce and he promised to meet her and go over the organization's finances. She said he never showed up and then cut off contact with her.

Graney has not been accused of any wrongdoing.  She is currently involved with the family of Sandy Hook victim Victoria Soto, helping run an annual road race in Stratford, Connecticut, that has raised thousands of dollars to fund scholarships for students studying to become educators.

Graney apologized Thursday to the families of Sandy Hook for any additional pain that Bruce's actions had caused, noting she did what she could to stop it.

"There were people who told me to keep quiet and to let this go but, I knew I couldn't live with that decision," she told The Associated Press. "I am ready for the closure that this plea deal will provide and I hope this will teach others a hard lesson about charity, philanthropy and doing the right thing."