A Massachusetts State Police barracks on Martha’s Vineyard — a building normally associated with law enforcement and public safety — has become the scene of a sexual assault investigation after a woman was reportedly seen running into the street partially undressed.

But authorities say neither the woman nor the man involved was a Massachusetts State Police employee.

According to the WBZ-TV I-Team, the incident unfolded in late August at the State Police barracks in Oak Bluffs, where troopers assigned to Martha’s Vineyard can stay while working on the island.

Sources told CBS Boston that a trooper working on Martha’s Vineyard for the summer had allowed a male friend to spend the night at the barracks.

At some point during the evening, a woman was reportedly seen fleeing from that man and running into the street.

She was partially undressed.

The woman then encountered a passing motorist and reported that she had been sexually assaulted.

The allegation has now triggered two separate lines of inquiry: a criminal investigation being conducted by Oak Bluffs police and an internal affairs investigation by Massachusetts State Police.

A Friend Was Allegedly Allowed to Stay Inside the Barracks

The location of the alleged assault is one of the most unusual aspects of the case.

The Oak Bluffs barracks is not simply a local police station. It serves Massachusetts State Police operations across Martha’s Vineyard, an island located about seven miles off Cape Cod and accessible primarily by ferry and airplane.

Troopers assigned to work on the island can also stay at the barracks.

According to sources cited by the WBZ I-Team, one of those troopers allowed a male friend to stay there overnight while the trooper was working on Martha’s Vineyard during the summer.

Authorities have not publicly identified the trooper, the man or the woman.

It is also unclear from the information released so far exactly how the woman came to be inside the barracks or what occurred before she was seen leaving the building.

Those questions remain part of the ongoing investigation.

What authorities have confirmed is that the reported assault involved two people who were not affiliated with Massachusetts State Police.

That distinction has become important as officials explain who is responsible for investigating what allegedly happened.

The Woman Reportedly Ran Into the Street

Sources familiar with the incident told the I-Team that the woman was seen running away from the man and into the street.

She was reportedly partially undressed at the time.

A passing motorist then encountered her, and the woman said she had been sexually assaulted.

That report eventually led Oak Bluffs police to launch a criminal investigation.

The details released publicly remain limited. Police have not announced an arrest or criminal charge, and authorities have not released the identities of anyone involved.

Because the case remains under investigation, the allegation has not been proven in court.

Still, police have taken significant investigative steps.

Police Obtained Search Warrants for the State Police Barracks

The Oak Bluffs Police Department said investigators established probable cause and obtained court-authorized search warrants during the investigation.

Those warrants included searches executed at the Massachusetts State Police barracks itself.

That means local police investigators were authorized by a court to collect evidence from a facility operated by another law enforcement agency.

Oak Bluffs police emphasized that they are conducting the criminal investigation independently.

Massachusetts State Police General Headquarters has cooperated with requests connected to the investigation, and State Police officials have also communicated with the Cape and Islands District Attorney’s Office about the case and the evidence gathered so far.

Oak Bluffs police stressed that the State Police are not participating in the criminal investigation itself.

That separation appears designed to avoid a conflict of interest given that the alleged incident occurred inside a State Police facility and reportedly involved a guest who was allowed to stay there by a trooper.

State Police Have Opened Their Own Internal Investigation

While Oak Bluffs police investigate the alleged sexual assault, Massachusetts State Police are examining a different question internally.

The department has opened an internal affairs investigation.

State Police confirmed that officials became aware of the reported assault at the end of August and said they were cooperating with the local investigation.

The department has not publicly explained exactly what its internal investigation is examining.

However, the circumstances raise obvious administrative questions about how a civilian guest came to be staying overnight at a barracks used to house troopers assigned to Martha’s Vineyard.

CBS Boston reported that the man was there because a trooper working on the island had allowed him to stay.

No public disciplinary action against that trooper has been announced.

State Police also stressed that both people directly involved in the reported assault were civilians with no affiliation to the department.

Two Investigations, Two Different Questions

The unusual structure of the case means the criminal and administrative investigations are examining different issues.

For Oak Bluffs police, the central question is what happened between the woman and the man inside the barracks and whether the evidence supports criminal charges.

Investigators can examine physical evidence, witness statements and any other material obtained through the court-authorized warrants.

The Cape and Islands District Attorney’s Office may ultimately become involved in determining whether charges should be pursued.

For State Police internal affairs investigators, the focus is on conduct involving department personnel and policies surrounding the barracks.

That could include determining whether rules were violated when a civilian was permitted to stay overnight at the facility.

Authorities have not publicly announced the results of either investigation.

The Barracks Serves the Entire Island

The location also matters because Martha’s Vineyard has a unique geography.

Oak Bluffs is a town in Dukes County with a population of roughly 5,500 people. The larger island is separated from mainland Massachusetts and depends on ferries and aircraft for access.

The Massachusetts State Police barracks in Oak Bluffs covers the entire island.

During the busy summer tourism season, Martha’s Vineyard’s population grows substantially, bringing increased demand for police, emergency and transportation services.

The barracks therefore plays an important public-safety role.

That makes an allegation of sexual assault occurring inside the building especially sensitive, even though authorities say the two people directly involved were not members of the department.

Many Questions Remain Unanswered

As of the latest update, investigators have not publicly identified the accused man.

They have not disclosed the identity of the woman.

They have not named the trooper who allegedly permitted the man to stay inside the barracks.

And no criminal charges have been announced.

It also remains unclear whether the trooper was present when the alleged assault occurred or what relationship existed among the people involved.

Those unanswered questions are likely to become central as the investigation progresses.

For now, officials have confirmed several key facts.

A sexual assault was reported at the Oak Bluffs State Police barracks in late August.

The alleged victim and alleged assailant were not State Police employees.

Oak Bluffs police obtained court-authorized warrants and searched the barracks.

Massachusetts State Police are cooperating with the criminal investigation while conducting a separate internal affairs inquiry.

And local police say their investigation will continue independently wherever the evidence leads.

The setting may make the case unusual.

But investigators now face the same fundamental question present in any sexual assault investigation:

What happened inside that building before a woman reportedly ran into the street and asked a stranger for help?