There are dead bodies seen onscreen; nothing particularly graphic or gory, though some have bruises, burns, markings left on their skin, or are sometimes only skeletons due to years of decomposition.
We see Lily's two mutilated pet cats that she rescued from a shelter throughout the earlier seasons; one cat is missing an eye, and another is missing a leg. A.D.A. Kite refers to the cat as "Tripod".
"Sanctuary" features a woman, an old flame of Scotty's, who was killed by disembowelment after ingesting drugs that a dealer wanted to sell. The disembowelment is never shown onscreen, and is only talked about by other characters. Still, probably one of the most graphic deaths in the series.
Will Jeffries is shot at; his lung collapses. Lilly is shot at in her shoulder. Lt. Stillman is shot in the chest. In all three instances, the characters survive. Blood is seen.
References made to POW camps, genocide, executions of dissidents in communist Cambodia, and war crimes.
Some racial violence, including a black woman being gang-raped and suffocated to death, a black youth being lynched in front of a crying white father and daughter made to watch, references to the real-life murder of Emmett Till, and two little girls being shot at for being friends when one is white and the other is black.
Some of the cold cases are the result of hate crimes, including gay bashing. We see a gay law student kicked and beaten to death in the street at one point.
Murder victims die in various ways (mostly off-screen), including being dropped/thrown from bridges, ingesting potassium cyanide, being strangled, being beaten with objects, being stabbed, being shot at, and other various methods. The show features the actual killings sparsely and does not glorify them, although sometimes the killers are portrayed with little to no remorse.
Cases of psychiatric abuse are featured prominently; we see characters with burns on their heads and severe brain damage due to electrode convulsive therapy, and a woman with a swollen eye after a lobotomy.
We see various scenes of domestic abuse, including a man being beaten to death with a fire poker by his abusive wife, a woman being hit in the eye by an abusive husband and having one of her daughters murdered in front of her, and a boy being punched by his father for dating a Puerto Rican girl.
Some off-screen scenes of animal cruelty, including a rottweiler being used for dog fights in "Ravaged", a dog beaten and bloodied in "Frank's Best", a cat said to have been drowned by a mentally-disturbed girl in "The Sleepover", and live racehorses being shot at with machine guns at a country club in "Time to Crime".
There are multiple scenes of shootings. In "Time to Crime", a little girl is shot in the chest and killed. In "Rampage", a shopping mall is shot up by two disturbed teen boys, who make jokes about the dying people. A man is shot in the stomach and bleeds out. A woman trips and falls after being shot; her body is later seen. Blood is seen. An elderly man is shot and killed. A fry cook is shot and killed; his body is seen.
Multiple threats of violence are made, including a woman threatening a man that his penis may be cut off in "Who's Your Daddy", a man threatening that a little girl may be killed in "Fireflies", and a character threatening to put another character "out of his misery" in "Wishing".
Scenes of bullying; a mentally challenged man in "Wishing" is called a pansy retard and kicked and beaten; a boy is punched in the eye after starting a fight in "Fireflies", a boy is pushed off his bike by a goth kid in "Offender", and similar incidents.
A man in "Blackout" mentions unabashedly that he wished to see "scarab beetles feasting on her (his wife's) intestines." Scotty and Will are visibly creeped out.