After he recovers, he gave her a key to his penthouse, and an offer to join him when he leaves Central City. Citizen Cold was injured while escaping and collapses outside his car near Iris, who then brought him to her home. Citizen Cold was too late and Lisa was killed. Citizen Cold tried to rescue Lisa, but the Rogues attacked him for revenge on what he did to them. Later, Citizen Cold invited Iris West to dinner, but it was interrupted by calls that his sister Lisa has been kidnapped by the Rogues. When Eddie Thawne discovered the Snart murdered Nurblin and that the cold gun was stolen property, Citizen Cold confronts him before he can reveal this information, and freezes Eddie in a block of ice.
After Snart defeats Victor Fries, he returned to his home and saw a news report that his sister, Lisa, has been arrested for killing their brutal father. When Thomas Wayne and Adrian Chase refused, Snart did as well. He was contacted by Hank Henshaw to join the fight against Carter Hall and Kendra Saunders. Leonard then became a police officer and began killing criminals similar to the ones that Barry Allen encountered in the previous timeline. Snart asked Nurblin who else knew he had taken the weapon, and when Nurblin answered they were the only two, Snart shot and killed him with his newly acquired weapon. Labs that emitted a cold substance and glasses meant to protect against the glare the weapon caused. Nurblin first offered Snart a fire-based weapon, but he refused, saying "he did not need to heat things up, but slow them down." Next, Snart looked at a weapon stolen from the S.T.A.R. Snart later met with the arms dealer Basil Nurblin. In 1975, Leonard's father was arrested for attempting to steal the Maximilian Emerald, causing him to be sent to jail for 5 years. He was also the older brother of Lisa Snart and the son of the late Lewis Snart. Leonard "Lenny" Snart (born June 2, 1972-died by suicide), nicknamed Citizen Cold (or simply Cold) by the media, was the greatest hero of Central City before Wally West became the Flash.