The lawsuit also names the town of Westchester, where Diana Paz was first taken into custody.
The suit accuses the town and state police of failing to protect the intoxicated young mother while she was in their custody.
According to the lawsuit, Westchester Police released the drunken mom and a state trooper dropped her off at a BP gas station near the Eisenhower Expressway early in the morning of September 2 last year.
She had no purse or cell phone. Twenty minutes later, Paz was struck and killed by a truck while walking along the median of the expressway.
"Had the state police and the Village of Westchester done their job they never would have let this young woman who was intoxicated out of their custody and her son would have his mother today," said attorney Tim Cavanagh. "I don't know that they have a policy with bonding someone out who is intoxicated they say they won't do it but they did it in this case so that policy needs to be changed."
Paz's 5-year old son Erick is now being raised by his grandparents.
"My parents told Erick that God needed an angel and that he decided to take Diana because she was a beautiful and nice person and he needed an angel like that," said Diana Paz's sister Maria Paz. "Right now he does not understand but he does ask about her."
Diana Paz's mother Maria Guerrero, who only speaks Spanish, says it has been very difficult for her daughter knowing her grandson will be without his mother. She wants justice and she wants to know why law enforcement officials did not protect her daughter.
State troopers had booked the young mother on a DUI charge for allegedly driving on the wrong side of the Eisenhower.
Police videos taken at the Westchester Police station show Paz submitted to a search and fingerprinting, at times she stumbles as if drunk.
"Diana was picked up for a DUI she should of been punished for a DUI," Cavanagh said. "The state police knew Diana was intoxicated her blood alcohol level cannot be disputed we are suing because state police should of never released her."
"It has been very hard for all of us now Erick has to grow up without his mother," Maria Paz said.
A state police spokesperson will not comment on this case because it is in litigation.
Paz's family describes as an outgoing young woman who was attending college in Indiana at the time of her death.
She was studying criminal justice and her goal was to become a law enforcement officer.
The family's lawyer says they will let a jury decide what the value of her life was for her young son.