For Norley, head of the Borough Council's public-safety committee, May's incident was the last straw. In response, with unanimous council approval, he has proposed strengthening an ordinance designed to crack down on renter rowdiness by getting tougher on landlords.
Landlords are balking, but Norley says the current ordinance "has zero teeth."
Under the law - a variant of plans employed in other college towns - landlords are assigned points depending on the severity of violations at their properties.
Failure to mow a lawn or remove trash counts as one point, with heftier penalties for bad behavior.
Drug possession or disorderly conduct on the part of "tenants, owners, or occupants" is worth two points. Serving drinks to minors, dealing drugs, or committing rape generates three points for each offense.
The accumulation of 10 points can result in a suspension of the landlord's rental license, but by evicting their tenants, landlords can scrub all points from their records. Landlords are notified once they reach five points and must submit a written correction plan to the borough within 30 days.
The system includes some protections for landlords. Tenants must be convicted of - not simply charged with - a crime covered under the ordinance before a landlord can be assigned points. Landlords can be assigned no more than three points in 24 hours, in effect giving them grace periods to deal with problems.
But Norley's plan would scrap the 24-hour provision and strike the clause that lets landlords evict tenants to get rid of points.
Several college towns in the state, including State College - home to Pennsylvania State University's main campus - have similar systems. State College Borough Manager Tom Fontaine said landlords cannot evict tenants simply to wipe points from their records, although they can use eviction as a defense at a license-suspension hearing.
State College landlords can receive only three points in a 24-hour period, he said.
"We've found [the ordinance] to be effective," Fontaine said. "The goal is to get the landlords more involved."
In West Chester, some landlords argue that it is impossible for a landlord to curb all problematic tenant behavior, and say the borough is overreacting to the May incident on Walnut Street.
"How can someone be responsible [for a tenant's behavior] when you don't know what that person is going to do?" said John O'Connell, director of the West Chester Apartment Rental Association.
Keller-Williams real estate agent Dianne Horvath, who said she has dealt with problem tenants, said landlords must have the right to scrub points by evicting tenants.
"I had one house where the tenants were just terrible. I had noise violations, I had trash violations every week," she said. "In one month I was able to rack up quite a few points, and the only way I could keep my permit was to evict them."
In West Chester, Norley said residents of the borough's student-heavy southeast quadrant deserve tougher laws. On Walnut Street last week, several residents who have dealt with loud parties on the weekends for years said they would welcome stricter penalties.
"Without having more initiative taken by the borough, it becomes an undesirable place to live," said Heather Tuckman, a psychologist who lives on Walnut Street with her husband and son, 5. She said noise and nuisance levels had improved in recent years, but that "a different culture has to be brought in" for renters and homeowners to coexist.
Two blocks down, a few steps from the house that hosted the out-of-control party, students tell a different story.
"People who live here who aren't students should move," said Ross Miller, a junior majoring in international relations. The point system, he said, is about "as ineffective as those quiet-zone signs. It's pointless."
Before the proposed modifications to West Chester's point system could become law, council legal staff would have to draft wording for an official vote. In the meantime, Norley said, he is prepared for a fight.
"Of course they're going to attack me or attack council," he said. "I don't care. Nobody has a right to violate other people's rights."
Contact Aubrey Whelan at 610-313-8112, at firstname.lastname@example.org or on Twitter at @aubreyjwhelan.