However, the Manhattan District Attorney's Office has declined to prosecute the two friends charged along with Garcia.
Two other people were questioned over the stabbings, but were released.
But following additional interviews with witnesses, prosecutors determined there is no evidence Varella or Hernandez were involved in the assaults.
The arrests came after several people were rounded up early Thursday and questioned in connection with the homicides, according to police.
Police say two friends headed home from a night out clubbing were stabbed to death early Sunday. Authorities said a brawl started after they tossed a bag of beer bottles that accidentally hit a man.
A third man was slashed but survived the attack, which took place early Sunday morning on a Brooklyn-bound train in Lower Manhattan.
The suspect escaped and ran from the Christopher Street station, becoming the focus of an intense manhunt.
He was described as a Hispanic man in his 20s, about six feet tall, with a medium build.
The victims were both 24-year-old men who were stabbed multiple times in the torso. Both were pronounced dead on arrival at St. Vincent's Hospital. They were later identified as Darnell Morel and Ricardo Williams, both of Brooklyn.
The third victim, identified only as a 23-year-old man, suffered stab wounds to the arm and neck and was treated at St. Vincent's.