The First 48 Season 18

In Tulsa, Okla., detectives suspect a random roadside encounter when they find an unidentified cyclist gunned down in the middle of an intersection outside the airport.

In Mobile, Ala., a 70-year-old Vietnam vet is found beaten to death in his home, where detectives discover cryptic threatening letters; in Tulsa, Okla., a random shooter reveals startling new information on a cold case.

When a father of three is executed on his front porch, Gwinnett County Homicide discovers that those closest to him are hiding a dark secret.

When an innocent bystander protecting a young woman is gunned down, detectives scramble to learn who fired the fatal shots before anyone else gets hurt.

In Mobile, Ala., a young man is murdered at his girlfriend's house when drive-by shooters unload several dozen rounds at the home; in Tulsa, Okla., a Jeep is found crashed along the highway with a man sitting inside, shot dead.

A beautiful teenager found naked and shot to death in an Atlanta park. With no evidence to work with, rookie detective Andre Lowe struggles to unravel the mystery. But the viciousness of her mysterious death evokes the sympathy of the entire Homicide Unit who pitch in to identify her and recreate her last hours on earth from tiny clues. The case captures the hearts of the public and, with tips flooding in, the detectives work round the clock to try to find her killer/killers.

In Mobile, Ala., a street fight escalates to a shooting that leaves a man dead in his front yard; in Tulsa, Okla., a drive-by shooting stemming from a gang feud claims the life of a 16-year-old girl, while her boyfriend clings to life.

In Mobile, Ala., the murder of a 19-year-old becomes personal when the team learns that the victim is Detective Jermaine Rogers' cousin; in Tulsa, Okla., a 31-year-old mother is gunned down in front of her home by an unlikely suspect.

In Atlanta, a stranger guns down a new father in a parking lot; in Georgia's Gwinnett County, a man is stabbed more than 20 times when someone he trusts turns against him.

When a young man goes missing in Tulsa, Okla., detectives must crack a family's code of silence in order to find him.

In Atlanta, a woman is found dead in a garbage can, and a young man is ambushed by neighborhood bullies.

In Atlanta, after his mother reports him missing, a man is found dead, naked and shot twice in his bedroom.

In Mobile, Ala., a 68-year-old woman goes missing after checking into a casino where she had lost millions.

In Georgia's Gwinnett County, a teenager is gunned down outside a nightclub when he winds up at the center of a gang feud.

When a young man is found executed in the street and a second victim is shot nearby, detectives scramble to track down the dangerous gunman before he kills again.

In Tulsa, Okla., a barrage of gunfire kills a man while he's sitting in his car, with his 2-year-old daughter in the back seat; an elderly Atlanta man is burned alive in a building fire suspected to be arson.

In Mobile, Ala., a man who turned his life around is gunned down in cold blood; detectives need to know if his troubled past came back to haunt him.

When a potential spree killer targets the most vulnerable in Tulsa, Okla., Detective Max Ryden must stop the murderer before he kills again.