Harvard and Cambridge police arrested a University custodial worker Tuesday night after he allegedly groped a graduate student at the intersection of Mt. Auburn and Holyoke Streets around 8 p.m.

Using footage from surveillance cameras, police arrested Geremias Cruz Ramos, 27, of Revere, Mass., around 10 p.m. Ramos is an employee of Harvard University Custodial Services in the Holyoke Center, according to Cambridge Police Department (CPD) spokesperson Frank D. Pasquarello.

This indecent assault, the sixth in four months in the Harvard Square area, is the only case for which an arrest has been made.

Police said Wednesday they have not yet determined whether Ramos is responsible for any of the other indecent assaults.

Ramos was arraigned Wednesday morning and charged with one count of indecent assault and battery, according to spokesperson for the Middlesex County District Attorney’s office Seth I. Horowitz. He pleaded not guilty.

In this latest incident, the victim, a Harvard graduate school student, told police that the suspect groped her and casually walked away until he saw her call the police on her cell phone. He then fled toward the Holyoke Center, according to Harvard University Police Department (HUPD) spokesperson Steven G. Catalano.

When CPD and HUPD patrols arrived on the scene, officers searched the area for the suspect.

“Because we hired extra people in light of last two incidents, there were extra bodies on duty last night,” Catalano said Wednesday.

Because Ramos had fled in the direction of the tunnel that passes under University Health Services (UHS) from Holyoke Street to Dunster Street, police watched footage from surveillance cameras in that area, Catalano said.

“We got a pretty grainy shot of the offender where the offender was wearing a specific piece of clothing. HUPD recognized the clothing worn by a contract custodial person,” Catalano said.

The victim then identified Ramos out of a group of custodians that police had gathered from the area.

Ramos is an employee of Sodexho, a food and facilities management services company that Harvard outsources, according to Sodexho spokesperson Stacy Bowman-Hade.

Pasquarello said it makes sense that the suspect in this case is an individual who knows his way around the campus.

“We’ve had plain-clothes and uniformed officers out there,” he said. “We thought it was a strange turn of events that we were getting all these indecent assaults in the area. We kind of felt it was somebody very familiar with the area.”

CPD is investigating whether Ramos is connected to the five other sexual assaults in the Harvard Square area over the last four months.