Authorities said the pair enlisted student dealers and customers at their alma mater, the Haverford School, and at Lower Merion, Harriton, Conestoga, and Radnor High Schools - all considered among the state's elite. The network also allegedly sold drugs at a few colleges.
Investigators said the pair demanded that their dealers move at least a pound of marijuana a week, and offered them incentives, such as discounts on drugs and the ability to buy on credit.
"It was a business - an illegal business, but they were using very traditional business practices," Montgomery County District Attorney Risa Vetri Ferman said during a news conference announcing the arrests.
Six other men and one woman were charged in the ring, as well as two juveniles - 17-year-olds from Radnor and Lower Merion High Schools. The charges - including conspiracy, drug distribution and sales - could land them in prison for years.
The defendants appeared before a district judge in Lower Merion on Monday. Most were released on bail. Scott had been jailed since March 1, with bail set at $1 million cash.
Both he and Brooks played lacrosse at the Haverford School as students and later coached there.
Scott briefly attended Connecticut College and in 2010, authorities said, moved to San Diego, where he worked at a medical marijuana dispensary.
He returned to Pennsylvania in October because his girlfriend ended their relationship, and ultimately moved into a Haverford apartment, police said.
By December, Scott had spent all his money and decided "to sell marijuana because he noticed the marijuana being sold on the Main Line was of poor quality," according to an affidavit filed with the charges.
Brooks attended the University of Richmond on a lacrosse scholarship but withdrew after a semester. He told investigators he started selling the drugs because he was having problems at home and wanted to move from his parents' house, court records said.
Besides marijuana, authorities said, the pair also peddled cocaine, hash oil, and ecstasy.
Lower Merion Police Superintendent Michael McGrath said authorities launched their investigation in January after confidential informants - current or former students at the schools - told police about drug dealing. Assisting were investigators from Delaware, Chester, Northampton, and Adams Counties and Philadelphia.
Informants eventually made "controlled buys" for police, who then got warrants to search the suspects' homes.
There, police said, they found marijuana and cocaine, $11,035 in cash, and weapons including a loaded AR-15 assault rifle and a loaded 9mm semiautomatic pistol. Also seized were cell phones used by Scott and Brooks.
Their texts suggest Scott was the veteran and Brooks his aspiring protégé.
"Idk [I don't know] what you make a week but I want to make 2 if I do this," Brooks wrote Scott, according to the affidavit. Police said "2" refers to $2,000 a week.
Later, Brooks allegedly wrote to Scott: "Every Nug on the mainline is about to come from you and me." Nug is street slang for a marijuana plant's bud portion, police said.
News of the arrests spread quickly through the high schools on Monday.
"It is crazy to think people around here can get guns and drugs like that and not be caught before they did," said George Walker, a senior at Radnor High School.
At the Haverford School, parent Daria Pew said she was glad the arrests occurred.
"I'm glad they are getting to the bottom and discovering what is going on for the sake of the kids at the school," said Pew, of Bryn Mawr, and the mother of an 11th grader.
The school's headmaster, John Nagl, said an assistant district attorney had alerted him Sunday night of the pending announcement.
"This is obviously deeply distressing," added Nagl, who said he did not know the alleged ringleaders. "We prepare boys for life. This is not the kind of life we prepare them for."
A spokesman for the Lower Merion School District said officials there were disheartened by the allegations. "But Lower Merion and the Main Line are not immune to these kinds of issues," spokesman Doug Young said.
Richard Gusick, curriculum director for the Tredyffrin/Easttown School District, which includes Conestoga High School, said officials just learned Monday of the charges, but had been aware of efforts to investigate drugs in the schools.
"As always, we stand ready to assist law enforcement officials any way we can if and when they request our involvement," he said.
Also charged in the case, authorities said, were Daniel R. McGrath, 18, of Glenolden, a current student at the Haverford School; John C. Rosemann, 20, of Connecticut, who was at Lafayette College; Christian S. Euler, 23, of Villanova, a student at Lafayette; Garrett M. Johnson, 18, a Haverford College student from New York; Reid Cohen, an 18-year-old Haverford College student from Englewood Cliffs, N.J.; and Willow L. Orr, 22, and Domenic V. Curcio, 29, both of Philadelphia.
District Judge Kathleen Valentine set their preliminary hearings for May 6. One of the defendants gulped and looked as though he were trying to choke back tears as Valentine spoke.
None of the defendants or their parents wanted to comment.
Greg Pagano, the attorney for Brooks, said his client "regrettably lost his way" after sustaining a serious injury. Pagano did not elaborate on the injury, but said he was suffering from depression when he and Scott became a team.
"He was at a very susceptible point in his life," Pagano said of Brooks. Brooks, Pagano said, "is willing to accept responsibility for what he did in this case."
Brooks' parents were set to post a portion of his $250,000 bail. Outside the courtroom, Brooks' father told his son's attorney that "I have to go to the bank."
Scott was arrested in the drug case while being on probation for unrelated charges.
Inquirer staff writers Kathy Boccella and Laura McCrystal contributed to this article.