(CNN) -- Four gang members potentially face life in prison without parole after being convicted Friday of using violence and intimidation to extort "rents" from drug dealers and suppliers on their Los Angeles turf, a federal prosecutor's office said.
This scheme ended up claiming the life of a 3-week old baby, who was shot in a stroller by gang members targeting a street vendor who refused to pay $50 to members of Columbia Lil' Cycos, a "clique" of the 18th Street gang, said the U.S. Attorney's Office for Central California in a press release.
The street vendor, who was next to the stroller at the of the September 15, 2007 incident, was shot four times but survived.
A total of 43 Columbia Lil' Cycos "members and associates" were charged in 2009 with being part of the broader scheme, in which an attorney Isaac Guillen laundered more than $1.3 million in drug and extortion funds that went toward that gang unit and Mexican Mafia member Francisco "Puppet" Martinez.
Some 37 of those have been found guilty, after Friday's conviction of 35-year-old Eduardo Hernandez, 31-year-old Vladimir Iraheta; 31-year-old Leonidas Iraheta, and 35-year-old Javier Perez.
A jury found these four guilty Friday "of a host of federal offenses" after an eight-week trial. They are set to be sentenced in September.
"The members of the 18th Street Gang, including those convicted today, thought that they controlled neighborhoods and territory within this city," U.S. Attorney André Birotte Jr. said. "Today's verdicts prove otherwise, and law enforcement at every level will work together to continue to make our streets safe."
Prosecutors argued that Columbia Lil' Cycos pressured "narcotics suppliers and street dealers" to give them money -- typically, a cut of their sales -- in order to hawk drugs in an area adjoining MacArthur Park in the Westlake district of Los Angeles.
Besides authorization to sell drugs, the "rent" money paid for "protection from rivals."
And if they didn't pay, they'd be punished.
According to evidence presented in court, Hernandez as well as Vladimir and Leonidas Iraheta made "thousands of dollars a week extorting the street vendors," the U.S. Attorney's Office said.
After the baby's death, Columbia Lil' Cycos leaders ordered the shooter in that incident be kidnapped. He was sent to Mexico and was, in a remote area, the victim of a strangulation attempt. "But unbeknownst to the would-be killers, the shooter survived the attack," the prosecutor's office said.