Investigators are urging the public to come forward as there may be more victims of an alleged serial sex offender who attacked a woman at a popular Halloween attraction.

Edward Eisenhard, 38, is facing a slew of charges after prosecutors in Bucks County, Pennsylvania say he sexually assaulted three female victims; one of them was under 12 years old.

"There are real monsters in the world," said District Attorney Joe Khan during a Tuesday news conference.

He went on to say the suspect is a "highly dangerous recidivistic sex offender."

One of his alleged attacks happened at Valley of Fear, which is a haunted hayride attraction in Feasterville, Pennsylvania.

Eisenhard is accused of strangling and sexually assaulting a victim while he was on a break while working at the attraction.

A criminal complaint says on September 25, the attraction's opening night, the suspect approached an employee who was working alone and "grabbed the victim tightly by her throat to the point that she had difficulty breathing, pinned both of her wrists above her head against a wall, made sexual comments, and indecently assaulted her over her clothing."

Valley of Fear fired him the next day. Two days after he was fired, he allegedly sexually assaulted the victim again at Five Below in Hilltown Township — where he also worked.

The victim told investigators Eisenhard, who was her boss, restrained and sexually assaulted her as she was cleaning the back stockroom of the store.

He was arrested on October 1.

Before those cases — investigators say he also "repeatedly" abused and sexually assaulted a victim under 12 years old at a home in Springfield Township.

Detectives with the Bucks County District Attorney’s Office discovered additional allegations of this behavior at both of Eisenhard's workplaces and "strongly believe that there are additional victims."

Eisenhard is currently in jail after he was unable to post bail following his initial arrest.

His charges were upgraded Thursday, and the DA is requesting that he be held without bail.

Fox News Digital has reached out to Valley of Fear and to Five Below for comment.

📩 Send me a story idea: kelsie.cairns@fox.com

📸 Instagram: kelsiecairns_tv

🎥 Facebook: Kelsie Cairns