The complaint charges Brown with eight counts — two of assault to murder with a firearm, two of attempted assault and battery with a firearm, possession of a large-capacity firearm, carrying a firearm without a license, possession of ammunition without an FID card, and discharging a firearm within 600 feet of a building.

The meltdown began at 12:10 p.m. Monday, the complaint says, when Brown's parole officer rang Boston police in a panic. The officer told BPD that Brown — a known crack-cocaine user — had just called him to say he had relapsed and was, in the parole officer's words to investigators, "ready to end his life."

The officer had already been tipped off that morning, according to the complaint, by another resident of the same rooming house, who told him Brown was "off his rocker" and had been "getting high all night."

The officer raced to Brown's Boston address. Brown wasn't home. Minutes later the officer's phone lit up — a FaceTime call from a number he didn't recognize.

It was Brown, the complaint says, standing inside a kitchen and waving a semi-automatic rifle.

"These people are gonna f---ing pay," Brown told the officer, per the complaint. "I'm not going back to prison."

Brown then boasted to the parole officer about murders he claimed to have committed in the past — including, he said, killings he was never caught for, the complaint states. The officer snapped a screenshot of Brown's face, killed the call, and alerted Boston police.

The complaint says Brown had been discharged from McLean Hospital — the Belmont psychiatric facility — the previous Friday. Per the document, he had been diagnosed with PTSD, anxiety and depression. The parole officer told investigators he believed Brown was under the influence of drugs during the FaceTime call.

Law enforcement scrambled. Boston police obtained a search warrant and pinged Brown's regular phone number through the U.S. Secret Service, which narrowed the gunman's location to a 1,000-meter radius inside Cambridge, according to the complaint. The Parole Department then pulled a second warrant to tighten the cone — by 1:21 p.m., the complaint says, Brown's phone was pinging within 100 meters of Kelly Road and Pleasant Street.

Before officers could close in, Brown called the parole officer one more time. He told the officer he was no longer Tyler Brown, the complaint states — he was now operating under his "shooter name." He kept waving the rifle and again vowed he was not going back to jail.

Sometime after that final call, per the complaint, Brown walked onto Memorial Drive and began firing his rifle "in an erratic fashion."

A Massachusetts State Police trooper rolled up and Brown opened fire on him, the complaint says. The trooper returned fire. So did a passing motorist — described in the complaint as an ex-Marine and former firearms instructor with a Massachusetts license to carry — who pulled a Glock 9mm out of a safe in his backseat and, per the document, emptied all eight rounds at the gunman before taking cover behind a tree. Brown went down with wounds to his extremities.

State police recovered the weapon between the road and the bike path: a multi-caliber BCI Defense Model FF-15 rifle with a scope, according to the complaint. Investigators counted more than 60 spent rounds at the scene. Brown did not have a license to carry.

The complaint confirms Brown was on dual supervision — parole and probation — when he pulled the trigger Monday. His parole had begun May 21, 2025, the document says, and was set to terminate at the end of this week. Prior convictions on his record, per the complaint: armed assault to murder, attempted assault and battery with a firearm, three counts of assault with a dangerous weapon, carrying a firearm without a license (second offense), carrying a loaded firearm without a license, possession of a large-capacity firearm, assault and battery with a dangerous weapon, and witness intimidation.

Brown is being held under guard at Beth Israel Hospital, where he is recovering from his gunshot wounds, and is expected to be arraigned once he is medically cleared.