The officer was reported to NIU campus police by the female victim last Friday. Police Sgt. Alan Smith said the incident allegedly happened in Cortland while Rifkin was off duty Oct.14.
NIU police conducted a preliminary investigation and fired Rifkin from his job.
Rifkin turned himself in Tuesday to authorities after a warrant was issued for his arrest. He was released that night posting a $15,000 bail.
Police said officers conduct routine dormitory building checks, file reports and respond to complaints by students. However, the police department has a strict "no-fraternization" policy with students, faculty, and staff at the university.
"We take out job seriously in providing the best service to this campus and community, " Smith said. "This type of behavior is not indicative of the behavior of members of this department."
Cortland police said they have respectfully backed out of the case, leaving the situation to NIU police.
Rifkin's next court date is set for Friday Nov. 4.