BRIDGEWATER — A reward is being offered for information leading to the arrest of the individual responsible for the sexual assault of a woman at Duke Island Park on July 18.

The woman told police she was riding her bike around 9 p.m. and stopped to use her cell phone at which point an unknown man came up behind her and held a knife to her throat, according to the Somerset County Prosecutor's Office.

He asked for money after which he sexually assaulted her in nearby bushes before leaving the area on a bicycle riding in the direction of Raritan Borough.

Crime Stoppers of Somerset County is offering a $2,500 reward. Anyone with information can contact the Somerset County Prosecutor's Office Sex Crimes Unit at 908-231-7100, the Bridgewater Township Police Department at 908-722-4111 or via the STOPit app.

Police said he was described as between 5 feet 4 inches and 5 feet 6 inches, 150 to 175 pounds, with a medium to stocky build and an olive to dark skin complexion. The suspect was said to be roughly in his 30s, with short black hair, and was last seen wearing a black hooded shirt and dark pants.

Duke Island Park is a 343-acre county park along the Raritan River with a visitor center, several bike paths, picnic groves and a softball field.

Previous reporting by Erin Vogt was used in this report

Contact reporter Dan Alexander at Dan.Alexander@townsquaremedia.com or via Twitter @DanAlexanderNJ

LOOK: 20 Fascinating Photos From the First Modern Olympic Games in 1896

To celebrate the history of international sports cooperation, Stacker took a look back at that groundbreaking event in Athens, when the modern Olympics were born in 1896. Keep reading to learn more about the athletes, spectators, and sports at that iconic event.

This spectacular Somerset County home is for sale

NJ words that should be added to the dictionary

13 words submitted by Steve Trevelise's followers for inclusion in the Dictionary — because somebody's got to explain New Jersey to the rest of the country.

More From New Jersey 101.5 FM