Melvin Collins was born in 1910 in Exmore, Virginia, into an African American family. Throughout his life, he exhibited violent tendencies, including previous imprisonments for shootings and an incident where he attacked his brother with a knife. Family members reported that Collins experienced periods of mental instability following a head injury in 1940. He spent time as a migrant worker across the Mid-Atlantic states and was known to hunt small game. In late October 1948, Collins arrived in Chester, Pennsylvania, and rented a second-floor room at 233 Market Street in the Bethel Court neighborhood. Neighbors described him as having a "hot temper," and he was known to modify his ammunition to act as dum-dum rounds.

On the morning of November 6, 1948, at approximately 8:15 a.m., Melvin Collins initiated a shooting spree from the window of his boarding room at 233 Market Street in Chester, Pennsylvania. He called out to a group of men below, "Call the cops," and dropped a dime before opening fire with a .22 caliber rifle. His first victim was Edward Boyer, who was shot in the chest and died instantly. As panic ensued, Collins continued firing at pedestrians and residents, resulting in eight fatalities and five injuries. ​

Among the deceased were Detective Ellery Purnsley, Chester's first Black police detective, who attempted to intervene and was fatally shot; Fred Casino, a passerby who tried to assist Purnsley; and seven-year-old Samuel Hill, who was struck while fleeing. The rampage lasted over an hour, during which Collins fired upon individuals both on the street and in nearby buildings.

Law enforcement responded with a task force of 78 officers, utilizing shotguns, submachine guns, and tear gas in an attempt to subdue Collins. After multiple tear gas canisters were deployed into his room, officers breached the door to find Collins deceased, having committed suicide by shooting himself through the roof of his mouth. The incident, known as the "Market Street Massacre," remains one of the deadliest mass shootings in Pennsylvania's history.