The symbol used by the Zodiac Killer to sign his correspondence. The Zodiac killer was a notorious thrill killer.
A thrill killing is premeditatedmurder committed by a person who is not necessarily suffering from mental instability, and does not derive sexual satisfaction from killing victims, or have anything against them, and sometimes does not know them, but is instead motivated by the sheer excitement of the act.
May 21, 1924: University students Nathan Leopold and Richard Loeb kidnapped and murdered 14-year-old Bobby Franks. Leopold, aged 19 at the time, and Loeb, 18, believed themselves to be Nietzscheanübermenschen who could commit a "perfect crime" (in this case a kidnapping and murder). Both were sentenced to life imprisonment plus 99 years; Loeb was murdered in prison in 1936, while Leopold was paroled in 1958 after serving 33 years, and died in 1971 of natural causes.
December 18, 1968 - October 1969: The Zodiac Killer terrorized the San Francisco Bay Area in northern California. In cryptic letters he wrote to newspapers, he claimed killing people "is so much fun. It's even better than killing wild game in the forest because man is the most dangerous animal. To kill gives me the most thrilling experience. It's even better than getting your rocks off with a girl."
September 8, 1988: Twenty-year-old bank clerk Janine Balding was abducted from a railway station at Sutherland, New South Wales, Australia by five homeless youths with extensive criminal records, and driven to nearby Minchinbury where she was repeatedly raped by three of the male offenders before being bludgeoned, hog-tied and drowned in a dam. The ringleaders, 22-year-old Stephen Wayne 'Shorty' Jamieson, 16-year-old Matthew James Elliott, and 14-year-old Bronson Matthew Blessington, were arrested the next day and later sentenced to life imprisonment plus 25 years without the possibility of parole; Blessington and Elliott are the youngest offenders to receive this sentence in Australian history.
September 15, 1990: Debra Holt, the mother of future world champion boxer Kendall Holt, and also known as Debra Holts and "Cocoa Tan", and three men she met while staying at the Alexander Hamilton Hotel, were convicted of killing a homeless man during an evening of senseless violence and crime in Paterson, NJ.
August 19, 1992: labourer and career criminal Andrew Peter Garforth murdered nine-year-old schoolgirl Ebony Simpson at Bargo, New South Wales, Australia. Garforth snatched Simpson as she walked home from school and threw her in the boot of his car, raped her repeatedly, bound her hands with speaker wire and weighted her schoolbag before throwing her into a dam where she drowned; he also joined the search for Simpson before being arrested. Garforth, who had 76 prior convictions, showed no remorse in court; he pleaded guilty and was sentenced to life imprisonment plus 30 years without the possibility of parole, with Justice Peter Newman calling the crime "chilling in the extreme".
February 12, 1993: Two 10-year old boys, Robert Thompson and Jon Venables, abducted and murdered toddler James Bulger in Liverpool, England. Thompson and Venables did not know the child but wished to kill someone. They were imprisoned for eight years.
October 29, 1995: Handyman and mechanic and convicted sex offender Paul Stephen Osborne raped and bashed to death 10-year-old Leanne Oliver and nine-year-old Patricia Leedie with a tree branch and wheel jack at Warana Beach, Queensland, Australia. After drinking 12 beers and smoking marijuana at a barbecue, Osborne took the girls to the beach for a swim; Leanne Oliver's father, Alby Oliver, found Osborne's wallet and the girls' bodies in sand dunes the next morning. When asked why he killed the girls, Osborne told police "I don't know. I don't know whether I blacked out or went crazy. They seemed pretty nice."  Osborne pleaded guilty and was sentenced to two consecutive sentences of life imprisonment plus 36 years without the possibility of parole; in sentencing Osborne, Justice Glen Williams said that he was ''beyond redemption".
April 19, 1997: New Jersey teens Thomas Koskovich and Jayson Vreeland ordered a pizza and ambushed two men who delivered it, Georgio Gallara and Jeremy Giordano, before going bowling. Koskovich and Vreeland told police they wanted to experience what it was like to commit murder.
July 17, 1997: Jesse McAllister and Bradley Price killed a man and a woman on a Seaside, Oregon beach only "to experience it [murder]."
September 30, 1997: 18 year old Todd Rizzo bashed 13-year-old Stanley Edwards to death with a 3-lb sledgehammer after he lured Edwards with a promise to hunt snakes in his backyard. Rizzo was convicted of the murder in 1999 and is currently on Connecticut's death row.
October 6, 1997: Bega schoolgirl murders: New Zealand-born career criminal Lindsay Hoani Beckett and Victorian prison escapee Leslie Alfred Camilleri murdered 14-year-old Lauren Barry and 16-year-old Nichole Collins at Fiddler's Green Creek, Victoria, Australia. After accepting an offer of a lift to a party, the girls were abducted, raped and tortured over the next 10½ hours before Beckett stabbed them on Camilleri's orders; Beckett and Camilleri then drove back to Yass and had breakfast. Beckett pleaded guilty and was sentenced to two consecutive sentences of life imprisonment with a non-parole period of 35 years in exchange for testifying against Camilleri, who was found guilty and sentenced to two consecutive sentences of life imprisonment plus 155 years without the possibility of parole. In sentencing Beckett and Camilleri, Victorian Supreme Court Justice Frank Vincent told Beckett that "You represent the dark in which our women and children fearfully walk", and told Camilleri that "Through your own actions, you have forfeited your right ever to walk among us again". Camilleri was sentenced in 2013 to an additional and cumulative 28 years for the murder of 13-year-old Prue Bird in Glenroy, Victoria on February 2, 1992. 
May 25, 2002: In what was described as a "sick game," Benjamin Sifrit and his wife Erika lured 32-year-old Joshua Ford and his 51-year-old girlfriend Martha "Geney" Crutchley to their Ocean City, Maryland condo and ordered them to disrobe before shooting Ford three times and stabbing Crutchley several times in the abdomen. Their bodies were then dismembered and disposed of in Delaware. After separate trials, Benjamin Sifrit was sentenced to 38 years imprisonment and Erika Sifrit to life imprisonment plus 20 years.
March 29, 2005: James Patrick Roughan, nephew of convicted killer Katherine Knight, and his friend, Christopher Clark Jones, stabbed and bashed 17-year-old Morgan Jay Shepherd over 130 times before decapitating him with an axe in Dayboro, Queensland, Australia after a lengthy drinking session; Shepherd's head was used as a puppet and bowling ball, according to witnesses. Both men were sentenced to life imprisonment with a non-parole period of 27 years; three youths who cannot be named because of their age were sentenced to two years detention for helping dispose of the body.
May 2005-August 2006: Two men in Phoenix, AZ (dubbed "Serial Shooter" by the media), Dale Hausner and Samuel Dieteman, went on a year-long random shooting spree. The murderous acts were called by the offenders themselves "Random recreational violence". Eight people were killed in the spree and 17 injured. Both men were found guilty.
June 18, 2006: Two 16-year-old girls, who cannot be named because of their age, strangled Eliza Jane Davis with electrical cable and buried her body under a vacant house in Collie, Western Australia, Australia, after the three attended a party. The girls told police they knew it was wrong to kill but it "felt right", and they did not regret Davis' death. Both girls were sentenced to life imprisonment with a non-parole period of 15 years.
December 17, 2006: Couple Jessica Ellen Stasinowsky, 20, and Valerie Paige Parashumti, 19, drugged, bashed and strangled their 16-year-old flatmate, Stacey Mitchell, before disposing of her body in a wheelie bin in Laithlain, Western Australia, Australia. Parashumti and Stasinowsky originally told police that Mitchell had moved to Queensland after an argument, but later confessed to the crime; they had discussed killing people on several occasions. Both women pleaded guilty and were sentenced to life imprisonment with a non-parole period of 24 years, which was increased to 31 years on appeal under new legislation, at the time the longest non-parole period handed down to a woman in Australian history. Justice Peter Blaxell said that had the women been convicted by a jury, he would have sentenced them to life imprisonment without the possibility of release on parole.
June 25, 2007–July 16, 2007: Two young men, Viktor Sayenko and Igor Suprunyuck, murdered 21 people from June 25, 2007 to July 16, 2007 in Ukraine. There is no apparent motive for the murders. Many photographs and videos were taken by the killers as a "memory" of their brutal spree; one video leaked onto the Internet. Both were sentenced to life in prison.
October 4, 2009: Teenagers Steven Spader and Christopher Gribble murdered Kimberly Cates and severely injured her daughter Jamie during a home invasion in Mont Vernon, New Hampshire. Both were assaulted with a machete; 17-year-old Spader admitted hacking Kimberley Cates to death with 36 blows to the head and torso. Spader had formed a club he called "The Disciples of Destruction" shortly before the murder, to whom he recruited his confederates. Spader designed a logo with the initials D.O.D. Spader told his recruits that the home invasion was to be a rite of "initiation" for club members. Both Spader and Gribble were sentenced to life in prison, while three other accomplices are also serving prison time. Apparently content with his life sentence, Spader informed his attorneys during an April 2013 resentencing hearing that he did not want a reduction in sentence, describing himself as “the most sick and twisted person you’ll ever meet.” He did not appear at the hearing.
August 16, 2013: in Duncan, Oklahoma, Chancey Allen Luna, 16, and Michael Dewayne Jones, 17, helped by James Francis Edwards, 15, shot Christopher Lane, 22, in the back with a .22-caliber revolver because, one of them said, '[They] were bored and didn’t have anything to do, so [they] decided to kill somebody.’