PHILADELPHIA — The cousins started small — break-ins, jewelry heists and traffic violations — but on Friday they were charged in a grisly crime spree that ended with police unearthing the bodies of four young men from two pits buried deep on a sprawling family-owned farm.

Police found the missing men after a grueling, five-day search in sweltering heat and pelting rain, but it’s still not clear why the 20-year-old suspects’ crimes escalated from petty offenses.

For Cosmo DiNardo, whose lawyer said he confessed to all four killings in exchange for being spared the death penalty, brushes with the law began in his early teenage years.

He was about 14 when the Bensalem Police Department first had contact with him. Over the next six years, he had more than 30 run-ins with its officers, department director Frederick Harran said, although court filings reflect only the minor infractions and traffic stops that came after age 18.

DiNardo enrolled at Arcadia University in Glenside in the fall of 2015 with hopes of studying biology and had an eye on international travel, according to a blog post announcing the incoming class.

“I’m going to go overseas, hopefully to Italy and the rest of Europe,” he is quoted as saying.

However, his time at the school was short. After making comments that unnerved several people on campus, public safety officials contacted the local police department. The university sent a letter to DiNardo’s parents saying said their son could face trespassing charges if he returned to the school, a person aware of the contents of the letter said, speaking to The Associated Press on condition of anonymity because they were not authorized to publicly discuss it.

A year and a day before he admitted to killing the missing men, lighting three of them on fire and using a backhoe to load the charred bodies into an oil tank that he buried more than 12-feet (3.7-meters)-deep on his parent’s farm, a family member had DiNardo involuntarily committed to a mental institution, Harran said.

Details of his institutionalization remain unclear, but he was barred by law from owning a firearm afterward. Nonetheless, when Bensalem police responded to a report of gunfire in February, an officer found DiNardo in his truck with a 20-gauge shotgun and extra ammunition. He acknowledged his history of mental illness, Harran said.

“A year later, here we are,” Harran said Friday. “The system is broken.”

Despite the mental health commitment and frequent interactions with police, DiNardo still managed to sell guns and marijuana in the area, according to a source familiar with DiNardo’s confession who spoke to the AP on condition of anonymity.

A police affidavit confirmed the source’s story — DiNardo lured each of the victims to his family’s 90-acre (36-hectare) Solebury Township farm under the guise of marijuana deals.

His first victim was set to buy $8,000 worth of marijuana but arrived with only $800, DiNardo told police, so he brought the 19-year-old Loyola University student to a remote part of the farm and shot him with a .22 caliber rifle. He buried Jimi Taro Patrick in a hole he dug with a backhoe. Yellow ribbons now line the Newtown street where Patrick lived with his grandparents.

Monsignor Michael Picard watched Patrick grow up at St. Andrew Catholic Church in Newtown, where he attended school and regularly attended Mass with his grandparents. The priest described Patrick as a very shy, very bright boy who won an academic scholarship to Loyola.