A convicted sex offender was sentenced to serve 18 years in prison as part of a plea agreement regarding a 2011 rape case in which DNA played a key role.

Donald E. Hackler Jr., 23, was sentenced Friday by Judge Douglas M. Rastatter in Clark County Common Pleas Court.

Hackler was also classified as a Tier III Sex Offender, requiring him to register with authorities for the rest of his life.

Hackler was originally charged with three counts of rape and one count each of attempted rape, intimidating a victim and gross sexual imposition, according to the Clark County Prosecutor’s Office.

The case stems from a March 27, 2011, incident, in which officers were dispatched to the 300 block of North Yellow Springs Street after a woman reported she was raped in an area near the 100 block of Cliff Park Road.

The victim told police she was sitting on some rocks when the suspect approached her and threatened her with a knife. He was accused of leading her into a wooded area, sexually assaulting her and then fleeing the scene.

Evidence was sent to the Ohio Bureau of Criminal Investigation, and a DNA test linked Hackler to the crime.

The victim also identified Hackler when police showed her a series of photos of possible suspects.

Hackler, previously classified as a Tier II Sex Offender, is already serving time in the Trumbull County Jail on a charge of failure to register as a sex offender when the warrant for a charge of rape was requested.