The handwriting was on the wall - in this case, on a bathroom wall at Avon Grove High School.

Authorities won't say what was scribbled Tuesday in black marker at the southern Chester County school. But the message has helped heighten concerns about repercussions in the school from Saturday's double homicide in Avondale. An Avon Grove student and a former student have been charged in the ongoing investigation.

Avon Grove Superintendent Gus J. Massaro said the words on the wall were linked to the weekend slayings.

Asked about the bathroom vandalism, which state police reported Thursday, Massaro said it underscored the proliferation of misinformation surrounding the homicides.

"The facts were backwards," he said, declining to elaborate. "What's unfortunate is that incidents that occur outside school can find their way inside and become disruptive to students . . . which we're working to prevent."

A statement on the district website expressed "sorrow over the recent violent incident in southern Chester County" and said district officials were "connecting with law enforcement to stay apprised of the ongoing investigations" in an effort to maintain a safe school environment.

In an e-mail, the neighboring Unionville-Chadds Ford School District made families aware of "disturbing violence reportedly involving rival gangs in the Avon Grove and Kennett School Districts."

On Wednesday, Avon Grove junior Stephen Andrew Daddezio, 17, was charged with aggravated assault, conspiracy, and related offenses for his role in a fight that erupted at an outdoor party and that led to the stabbing deaths of Cuahuctemoc Bedolla, 27, and Jose Rodriguez, 29, both of West Grove.

James L. Jones, 19, of West Grove, who attended the school last year, was arraigned Tuesday on charges that included first-degree murder and conspiracy, court records show. Bedolla's Facebook page identifies him as a 2003 graduate of Avon Grove.

The homicide investigation began when New Garden Township officers responded to Jennersville Regional Hospital in West Grove at 11 p.m. Saturday for a report that Bedolla was critically injured. He was flown to Christiana Hospital, where he was pronounced dead about an hour later of stab wounds, the criminal complaint said.

Investigators went to an address in Avondale where Bedolla had attended a party. Witnesses told police a fight had broken out after 10 p.m. among attendees and some uninvited guests. The area was so dark and remote that police did not find Rodriguez's body until Sunday morning; he, too, died of knife wounds.

One witness admitted driving a getaway vehicle for Daddezio and Jones, adding that Jones reportedly said, "I can't believe I stabbed that guy," according to the criminal complaint. Daddezio's cellphone contained text messages referencing the killings, the complaint said.

According to court records, both victims had criminal histories. According to Bedolla's, when he was sentenced in 2007 on weapons charges, he was ordered to avoid membership in any gang-involved criminal activity.

Law enforcement officials have declined to speculate on whether the weekend killings were gang-related, but Massaro acknowledged rumors were rampant - adding that misinformation, such as the message on the bathroom wall, had also circulated.

Gang tensions have simmered in southern Chester County for years, escalating after the 2003 gang-related slaying in Kennett Square of Fidel Ibarra, 22, of Wilmington. Since then, local, state, and federal law enforcement have met regularly to share intelligence on gang activity.

Kennett Square Police Chief Edward A. Zunino Jr. said even the possibility of gang involvement in a homicide put police on high alert.

"We know the element is here," he said, "and we're pretty aggressive in our efforts to stay on top of it."

Jones was held without bail at Chester County Prison; Daddezio was in the same prison after failing to post $250,000 bail. A preliminary hearing was scheduled for Dec. 16, court records said.

Anyone with information about the killings or the party is asked to call New Garden Township Sgt. Joseph Nangle at 610-268-2907, Ext. 100, or the Chester County detectives at 610-344-6866.

Contact staff writer Kathleen Brady Shea at 610-696-3815, kbrady@phillynews.com, or @brandywinebits on Twitter. Read her blog, "Chester County Inbox," at www.philly.com/chescoinbox.