Vyacheslav Solovyov, 37, from Yaroslavl, 280 km (175 miles) northeast of Moscow, was charged with murdering his two wives, his 14-year-old daughter, the mother of his third wife, a one-year-old boy and a police investigator, who he alleged was rude to him. He was also charged with the attempted murder of four other people.
The trial, which began this week at the Yaroslavl Regional Court, is due to be resumed once Solovyov is released from hospital and has undergone psychiatric tests. Two previous psychiatric examinations indicated that the accused was mentally fit to stand trial.
Solovyov's first victim was his wife, Olga, who he poisoned with thallium, having explained to investigators that he simply 'got tired of her.'
Thallium, known as 'The Poisoners' Poison,' is used to kill rats and has no smell, is tasteless and easily dissolves in water. Death is not immediate and it usually takes one to three months for the victim to die. If special tests are not carried out during the autopsy, the cause of death is normally put down to natural causes.
Following the death of his wife, Solovyov accidently poisoned his 14 year-old daughter after she ate some caviar he had prepared for a drunken neighbor.
He then murdered his second wife by giving her poisonous coffee to drink. The autopsy indicated kidney and liver failure which doctors said was caused by a tick bite.
His next victim was a local police officer, Valery Shcherbakov, who questioned Solovyov in connection with a stabbing in a local cafe in Yaroslavl. The serial poisoner later claimed that Shcherbakov was rude to him during questioning and he got rid of him by adding poison to the investigator's coffee.
As the string of murders went unnoticed, Solovyov focused on his common-law wife, Oksana Guryeva. During a visit to Oksana's mother, Solovyov sprinkled poison in a bottle of drinking water. Oksana, who is an athlete, survived, but her elderly mother died.
Medical authorities finally became suspicious after Oksana's sister, husband and their one-year-old son, who subsequently died, were admitted to hospital. Tests revealed traces of thallium, which led police investigators to Solovyov. He was eventually arrested in May 2007.
Although the serial poisoner confessed to most of the murders during questioning, investigators said his motives were unclear, but he obviously enjoyed what he had been doing and had become an expert in poisons.
The investigation established that while working in Yaroslavl, Solovyov amused himself by adding different substances to his co-workers' drinks and food, which caused vomiting and diarrhea, and Solovyov enjoyed watching his colleagues run to the toilet.
Russia's most prolific murderer is Alexander Pichushkin, 33, nicknamed the 'chessboard killer' for his habit of marking off his victims on the squares of a chessboard. He was convicted last fall of 48 murders, but Pichushkin says he took the lives of at least 60 people, although investigators said they have found no evidence to back up his claims.
