Below are five of the most talked about crimes in 2015. The list is compiled by news website Zing.
Nguyen Hai Duong, 24, hatched a plan to kill the family of his ex-girlfriend Le Thi Anh Linh, 22, in Binh Phuoc Province after she broke up with him in March.
He successfully persuaded his friend Vu Van Tien, 24, to join a scheme to rob the wealthy family.
At around 1:30 a.m. on July 7, the duo entered the house after Linh’s 14-year-old cousin, Du Minh Vy, opened the gate for them.
After killing Vy at the gate, they set their sights on the rest of the family, killing Linh, her 48-year-old father, Le Van My, her 42-year-old mother, Nguyen Le Thi Anh Nga, her 15-year-old brother, Le Quoc Anh, and her 18-year-old cousin, Du Ngoc To Nhu.
Police said the victims sustained fatal stab wounds to their necks and chests.
However, the life of My's and Nga's youngest daughter, an 18-month-old baby, was spared.
Duong and Tien then left the house with about VND4 million (US$180) in cash, five smartphones, an iPad and a laptop.
They were arrested four days later. On December 17, a Binh Phuoc court sentenced the duo to death on murder and robbery convictions.
According to the indictment, Vi Van Hai of Nghe An Province was caught in the act of picking some lemons on the tree of a neighbor by Lo Van Tho, a 24-year-old local, on July 2.
After a short quarrel with Tho, Hai did not leave but went into Tho's tent and ate the lemons.
They argued again and Tho tried to punch Hai, who then grabbed a knife in the tent and killed the other man.
He then went looking for Tho’s wife, Le Thi Yen, who was running away together with her 11-month-old son. While chasing the 26-year-old woman, Hai killed Tho's mother, 63-year-old Vieng Thi Duong, who was bathing in a nearby stream.
Hai was arrested 17 days after the murder. He was sentenced to death by a local court on September 30.
Dang Van Hung, 26, of Yen Bai Province was found guilty of murdering 32-year-old Tran Van Long, Long's 20-year-old wife Phan Thi Hoa, his two-year-old son and his sister-in-law on August 12.
Hung confessed that he killed Long's family after an argument over disputed farm land and water stream.
Hung and the victims are relatives.
All the victims were slashed to death by a knife used for farming.
Around 500 police officers searched for Hung after he and his 36-year-old girlfriend, Nguyen Thi Han, ran into a forest to hide.
Hung was arrested three days later.
He was sentenced to death on October 28 by a local court. Han did not face criminal charges as the police said she was forced by Hung to run away with him.
Relatives of Ngo Van Ha, 45, in Thanh Hoa Province broke the door of his house on the evening of November 1 after hours of losing touch with the family.
They found the man had hanged himself on the first floor. The bodies of his 42-year-old wife and two sons aged 12 and 23 were later found in three separate rooms on the upper floors.
The police found a death note, allegedly written by Ha, two recordings in his mobile phone and a large number of empty sleeping pill boxes.
Ha wrote in the seven-page death note that a business partner had cheated him and driven him to debt and despair.
He said he decided to kill his wife, their two sons and himself because he was unable to pay VND27.6 billion (US$1.2 million) of debt.
Vu Van Dan was arrested near his house in Gia Lai Province more than three hours after killing four people and injuring three others on August 23.
According to the police, Dan and his wife Nguyen Thi Lan went to the house of a neighbor, Le Trung Dung, to demand repayment of a debt.
But unable to get the money back, the two returned home where a quarrel broke out between them, and Dan attacked her with a machete.
Lan managed to escape with her son after sustaining a minor injury in her hand.
At around 2 p.m. Dan went out to find his wife but instead vent his fury on other people.
He allegedly ended up killing his sister-in-law, Le Thi Thom, 33, her eight-year-old daughter Vu Thi Van and two neighbors, Dang Dinh Van, 57, and Nguyen Thi Ngoc Lien, 41.
After the killings, he continued to attack people and injured his brother Vu Van Tuyen, 33, and two other neighbors, Vu Cong Doanh, 32, and Nguyen Thi Minh, 52.