An 80-year-old resident of Twin Oaks Villa Assisted Living in North Charleston was sexually assaulted in April and June, according to an affidavit.

The suspect, Nathaniel J. Richardson, 48, is charged with assault and criminal sexual conduct. He was being held Friday at Charleston County Detention Center in lieu of $40,000 bond, officials said.

At the time of the alleged assaults, Richardson was a maintenance worker at the facility, the affidavit states.