Ailina Tsarnaev, who told police she is 21 but is believed to be three years older, was charged with one count of aggravated harassment for telling a woman: "I have people that can go over there and put a bomb on you."
Lieutenant John Grimpel said the victim has a child with the father of Ailina Tsarnaev's children, but didn't reveal the nature of their dispute. Grimpel said Ailina Tsarnaev was released later that day and is expected to return to criminal court on September 3.
Ailina Tsarnaevs's brothers Dzhokhar Tsarnaev, 21, and the late Tamerlan Tsarnaev are accused of setting up the bombs that killed three people and injured more than 260 at the Boston Marathon on April 15, 2013. The brothers are also accused of killing MIT police officer Sean Collier after the bombing.
Tamerlan Tsarnaev was killed days after the bombings during a confrontation with police. Dzhokhar Tsarnaev is awaiting trial in federal court.
Ailina Tsarnaev and her sister Bella Tsarnaev have visited their brother at the federal prison where he's being held at Fort Devens in Ayer. They are believed to live together in New Jersey and New York with Tamerlan Tsarnaev's widow Katherine Russell and her son.
Ailina Tsarnaev was arrested once before in 2010 after being charged with impeding an investigation into counterfeiting at an Applebee's restaurant in Dorchester, and for failing to appear in court later. While she was not the one being accused of passing the counterfeit bill herself, police say she knew the people who did.