Matricide

Matricide is the act of killing one's mother. In the case of teenage daughters, it is often for one of two reasons. Either the daughter "snapped" (suddenly lost her temper) after suffering abuse or became an abuser herself. Few studies have been done to discover why children commit parricide, matricide or patricide.
Known or suspected matricides
Amastris, queen of Heraclea, was drowned by her two sons in 284 BC.
Cleopatra III of Egypt was assassinated in 101 BC by order of her son, Ptolemy X, for her conspiracy.
Ptolemy XI of Egypt had his wife, Berenice III, murdered shortly after their wedding in 80 BC. She was also his stepmother, or perhaps his mother.
In AD 59, the Roman Emperor Nero is said to have ordered the murder of his mother Agrippina the Younger, supposedly because she was conspiring against him.
Mary Ann Lamb, the mentally ill sister of essayist Charles Lamb, killed their invalid mother during an episode of mania in 1796.
Sidney Harry Fox, a British man, hanged in 1930 for killing his mother to gain from her insurance.
Battle of Okinawa, 1945: There are accounts in which Okinawan civilians killed their mothers to prevent them from being captured, raped, tortured, and/or killed by the invading American forces.
The Parker-Hulme murder case of 1954. This case was chronicled in the 1994 film Heavenly Creatures.
Jack Gilbert Graham killed his mother along with 44 people by planting a dynamite bomb in his mother's suitcase, that was subsequently loaded aboard United Airlines Flight 629 in 1955.
Charles Whitman killed his mother and wife before going on his killing spree at the University of Texas at Austin that killed 14 people and wounded 31 others, as part of a shooting rampage from the observation deck of the University's 32-story administrative building on August 1, 1966. He was eventually shot and killed by Austin police.
John Emil List murdered his mother, wife and his three children on November 9, 1971, making List also guilty of filicide and uxoricide. He was a fugitive for 18 years. He was apprehended on June 1, 1989 after an episode of "America's Most Wanted" aired. On May 1, 1990 he was sentenced to 5 life terms in prison.
Antony Baekeland murdered his mother, Barbara Daly Baekeland on November 11, 1972, at their luxurious London apartment. She had allegedly forced him to have sex with her, in order to "cure" his homosexuality. Savage Grace is a book and a movie based on this event.
Serial killer Edmund Kemper beat his mother to death in 1973, along with one of his mother's friends before turning himself in to the police. He had previously committed half-a-dozen sex-murders. Kemper had been psychologically abused by his domineering mother in his youth.
Ronald DeFeo, Jr. killed his parents and his four siblings in what would later become known as "The Amityville Horror House" (1974)
Bradford Bishop bludgeoned his mother, spouse and three children to death in 1976. He was indicted for murders and remains at large.
Jim Gordon, a session musician who played drums with Eric Clapton band Derek and the Dominoes bludgeoned his mother with a hammer and then stabbed her to death with a butcher's knife in 1983. In May 1984 he was sentenced to sixteen years to life in prison.
Susan Cabot, 1950s actress, was beaten to death in 1986 at her Hollywood home by her son Timothy Roman. He was convicted of involuntary manslaughter.
Lyle and Erik Menendez were convicted during a highly publicized trial in July 1996 for the shotgun killings of their parents in 1989.
Brett Reider, a 15-year-old boy in Omaha, Nebraska, stabbed his mother to death during a dispute in 1993. He was convicted of second degree murder and sentenced as an adult to 11-20 years. In 1996, his older sister, Alissa Reider made an HBO documentary: "Brett Killed Mom: a sister's diary", claiming both of them suffered years of constant verbal and physical abuse from their mother. Brett was released in 1999.
Aaron Brown, Indiana resident who at the age of 16 sat in wait with a shotgun until his parents came home one night, and as his mom walked through the door, he blasted her with the shotgun. He shot at his stepfather and missed, but eventually gunned him down. These crimes were committed in 1994. He is currently serving two life sentences at The Indiana State Prison in Michigan City, Indiana.
Luke Woodham, Mississippi resident who killed his mother in June 1997 before killing two more and wounding seven others in the Pearl High School shooting. Currently serving a life sentence at the Mississippi State Penitentiary.
Kip Kinkel (1982- ), an Oregon boy who was convicted of killing both parents as well as killing two students at his school on May 20, 1998.
Dr. I. Kathleen Hagen, a prominent urologist, killed her mother and her father in August 2000 and was acquitted on the grounds of insanity.
Yukio Yamaji, a 16-year-old living in Japan, killed his mother in 2000. After his release, he raped and murdered a woman and her sister in 2005. He was executed by hanging in 2009.
Dipendra of Nepal (1971-2001) reportedly massacred much of his family at a royal dinner on June 1, 2001, including his mother Queen Aiswarya, father, brother, and sister.
Nathan Ybanez, a 16-year-old Colorado boy, murdered his mother Julie Ybanez in June of 1998.
Erika di Nardo killed her mother and brother in 2001. See Novi Ligure Murder
Sef Gonzales, an Australian man who killed his father, mother and sister in 2001.
Linda Andersen (January 18, 2003) murdered by her two daughters.
Sarah Marie Johnson (1987- ), an Idaho girl who was convicted of killing both parents on the morning of September 2, 2003.
Noura Jackson was wrongfully convicted of killing her mother who was found dead with more than 50 stab wounds on June 5, 2005. The Tennessee Supreme Court overturned this verdict on the basis of prosecutorial misconduct. Prosecutor Amy Weirich withheld evidence that would have freed her.
Jasmiyah Kaneesha Whitehead (b. November 27, 1993) and Tasmiyah Janeesha Whitehead (b. November 27, 1993) are identical twins who were convicted in 2014 for the murder of Nikki Whitehead (their mother).
Joseph Nerone confessed to killing his mother by stabbing her multiple times on April 2, 2012.
Adam Lanza in the Sandy Hook Elementary School shooting shot and killed his mother along with 20 children, 6 other adults and then himself on December 14, 2012.