This is a thread listing the most infamous and/or brutal killings by street gangs or organised crime groups. People can feel free to add on to this list. its in no particular order or anything. ill start off.

Oakland Hells Angels
Mother and 6 year old twins murdered
Oregon Jury Convicts Man in 4 Killings Linked to Hell's Angels

A man who prosecutors say was under orders from a top Hell's Angels leader was convicted today of murdering a woman, her twin 6-year-old girls and a family friend 17 years ago.
The defendant, Robert G. McClure, 47, was sentenced immediately after the verdict to four consecutive life terms in prison.
Mr. McClure had claimed that he had been framed by the bikers club. He sat impassively as the verdicts and sentences were read. His lawyer, Lisa Maxfield of Portland, said he would appeal.

The jury in Washington County Circuit Court deliberated more than six hours over two days before returning the unanimous verdicts.
Judge Jon B. Lund called the trial one of the "most egregious" murder cases he had ever heard. He told Mr. McClure that he had killed "four innocent people in a heartless and coldblooded fashion."

Execution-Style Killings

On Aug. 7, 1977, Margo Compton, 24, was found dead in her home in the rural town of Gaston, along with her daughters, Sylvia and Sandra, and Gary Seslar, 19, the son of her boyfriend. Each had been shot in the head.
Ms. Compton's sister, Lynne Spieckerman of Gonzales, Tex., burst into tears when the verdict was announced. She and Bonnie Sleeper, who was Mr. Seslar's fiancee and who discovered the bodies, both hugged the prosecutors, Robert Hamilton and Robert Heard.

The prosecutors contended that Mr. McClure had been under orders from Odis Garrett to kill Ms. Compton in retaliation for her testimony against several Hell's Angels in a San Francisco prostitution trial.
Both Mr. McClure and Mr. Garrett, a leader of the Oakland, Calif., chapter of the Hell's Angels, were later imprisoned on drug charges.

Facing Extradition
Mr. Garrett, who was also charged in the killings, is serving time in a California prison on a drug conviction but still faces extradition to Oregon. He was convicted in the San Francisco prostitution case after Ms. Compton testified against him.

Several prison inmates testified that the two had talked about their roles in the killings. The inmates said they had agreed to testify for the state because killing children violated their code of conduct.
One prisoner testified that Mr. McClure had bragged about making Ms. Compton watch as he shot her daughters first and had claimed that they had died clutching their teddy bears.


'Infamous Case'
More than 75 witnesses testified, including members of the Hell's Angels and the Aryan Brotherhood prison gang. Many were brought into the courtroom in leg irons, handcuffs and waist chains.

Lou Barbaria, a senior investigator with the New York State Police, has been following the trial from across the country. "It's an infamous case in the law-enforcement circuit," Mr. Barbaria said. He cited a Federal court case in New York in which the Hell's Angels involvement in the death of Ms. Compton had been admitted as proof of the club's viciousness toward those who testified against them.

Rolling 60s Crips
Home invasion mass murders
The gang became notorious when several men identified as members of the Rollin' 60 were arrested by police investigating the murders of the family of Kermit Alexander, an All-American football icon.

On August 31, 1984, Alexander’s mother, sister and two nephews, ages 8 and 13, were murdered in South Central Los Angeles during a home invasion by members of the Rollin 60’s Neighborhood Crips, whose intended victims lived two doors away

Bounty Hunter Bloods
two officers executed
In 1993, two Compton Police Officers, James Wayne MacDonald and Kevin Michael Burrell, were killed execution style by a Bounty Hunter Blood Gang member.
February 22nd 1993 was a day no Compton cop would ever forget. It was nighttime as veteran officer K. Burrell and reserve officer Jimmy MacDonald rode together. Burrell was a 6ft 5inch 300-pound giant of a black man. He was an aggressive officer who loved to make the good felony arrest. Jimmy was a white officer, and was his last night riding in Compton because he just got hired fulltime as a police officer in northern California. This night would be their last night alive, as they were about to pull over one of the most ruthless “Bounty Hunter” Blood gang members around. His name was Regis Thomas. Within the last year, he was released from jail on a murder charge, due to fact the only eye witness to the case turned up murdered. Thomas grew up in Nickerson Gardens on Imperial Highway in L.A. In our opinion this large housing project, along with Imperial Courts and Jordan Downs are the worst places in L.A. You just don’t go into these projects at night, unless you have at the minimum four cops.

Officers again heard that one radio call, you never want to hear, as Compton dispatchers put out the radio call “shots fired at Rosecrans and Dwight Street, officers down”. When officers arrived, they found the police car facing west on Rosecrans Blvd. with its overhead lights going. In front of he car was Officer MacDonald laying in the street, shot numerous times, the worst was one shot to the back of the head at close range. Burrell was lying down by the curb also suffering from numerous gunshots. Burrell also shot in the head at close range and both were dead.

Our Police Department was in shambles. Kevin and Jimmy had been the first officers’ shot and killed in Compton. In addition, our personnel were paralyzed with grief, and unable to get a grip on the investigation. Chief Taylor made one of the best decisions of his career, he asked the Los Angeles County Sheriff’s Department for assistance. We had already lost two days of the investigation since the Department had been bombarded, and over whelmed with clues relating to the shooting. The Sheriff’s Department had the resources, but we had the gang intelligence, so a Task Force was formed. We were part of this Task Force and were proud to be a part of the arrest and conviction of Regis Thomas who is currently on death row.

Shower Posse
festival mass shooting
Oakland, New Jersey, in August, 1985, members of the Shower posse sprayed machine-gun fire on a festival crowd in Oakland, N.J. Three people were killed and more than 20 were wounded. Police say the purpose of the attack was to eliminate drug dealers in the rival Dog posse.
This incident resulted in the death of three persons, the wounding of 19 others and the seizure by police of 33 weapons.

Gambino Crime Family
Shamrock Bar murders
Following a five-week trial, a federal jury in Brooklyn today found Bartolomeo Vernace, a member of the administration of the Gambino organized crime family of La Cosa Nostra (the “Gambino family”), guilty of a racketeering conspiracy spanning 1978 through 2011.
Among the crimes he committed for the mafia, Vernace, together with two Gambino associates, murdered Richard Godkin and John D’Agnese in the Shamrock Bar in the Woodhaven neighborhood of Queens on April 11, 1981, after a dispute arose between a Gambino family associate and others in the bar over a spilled drink. The associate left the bar and picked up Vernace and a third accomplice at a nearby social club. A short time later, the three men entered the bar and gunned down Godkin and D’Agnese—the owners of the bar—as the bar’s patrons fled for cover.

Youngstown Mob
Marsh family murders/drug robbery murders
A former reputed Youngstown mobster in prison for a double murder in the Columbus area was indicted Thursday in a 39-year-old mass murder in Canfield Township, in which a General Motors security guard, his wife and their 4-year-old daughter were brutally murdered.

Investigators allege James P. Ferrara, 64, a former Youngstown mobster, fatally shot Ben Marsh, shot Marilyn Marsh from behind and beat her and beat Heather Marsh to death with his empty gun. Investigators found 1-year-old Christopher Marsh covered in blood and crawling on the family’s floor.

a GM supervisor found Ben Marsh, his wife Marilyn and 4-year-old Heather brutally murdered on Dec. 13, 1974 at their S. Turner Road home. Their 1-year-old son, Christopher, was found alive and covered in blood. Both Ferrara and Marsh worked at GM, according to sources. Ben Marsh was shot four times, Marilyn was beaten and shot once from behind and Heather was found beaten to death with a blunt instrument
he also commited two murders nine years later.

Records say Ferrara and two other men— Joseph A. Weeks, then 36, and Mark Jennings, then 26— at about 11:30 a.m. on March 6, 1983 went to 441A E. North Street, Worthington, about 12 miles north of Columbus. Records show the trio went to the home to steal a large amount of cocaine from two men, Fred Lemmens and Ed Hanna, who were inside the condo and partners in a cocaine-dealing scheme. Lemmens, Oppenheimer said, was a school teacher in the Ghanna area at the time and was inside at the time. Oppenheimer said Jennings and Hanna were cousins, and that they conspired to steal from Lemmens.

A witness at the time told police the trio knocked on the door and said “collecting” and “1136.” One man held a gun in his hand, reports say. Hanna opened the door. The look on his face, according to the witness, was of “utter horror.”

The witness said the door closed, but later heard three or four gunshots. She saw the three men get into a 1978 silver Monte Carlo and drive away. She said a man, who later turned out to be Ferrara, exited the home carrying a briefcase. Lemmens noticed a wink between Jennings and Hanna and began screaming he was being set up.

Oppenheimer said Ferrara snapped and pistol-whipped Lemmens. He then shot Lemmens and Hanna to avoid witnesses to Lemmens’ murder, Oppenheimer said.Officers found Hanna and Lemmens dead face down in the apartment’s kitchen. Hanna’s head was on a step and had been shot in the back of the head, reports say. Lemmens was face down with a phone cord wrapped around his hands. Investigators at the time noted he had been beaten in the head with a blunt object and shot.

Officers spotted the Monte Carlo Ferrara, then 34, was riding in on Interstate 71, while Ferrara watched the officers from the backseat, reports said. The car pulled into a truck stop in Mansfield.The trio was arrested. Officers found a Smith and Wesson .38-caliber gun wedged between Jennings’ seat and the door.

Ferrara, officers noted, had blood covering his arms and hands and was sitting on a brown coat. Under the arm of the coat, investigators found a bloody .38-caliber Colt Cobra revolver. Six rounds of ammunition were found in a stocking cap nearby, reports say. They also he had a large pocketknife. WKBN and WYTV archives say the Ben and Marilyn Marsh were killed with a .38-caliber revolver.