Jurijus Kadamovas was born on October 22, 1966, in Vilnius, Lithuania, which was part of the Soviet Union at that time. Little is known about his childhood or family background.

As an adult, Kadamovas emigrated to the United States. He settled in Los Angeles, California, where he was involved in business. He co-owned a fish aquarium store called Designed Water World, located on Ventura Boulevard. This business was a partnership with another man named Iouri Mikhel, who was born on April 9, 1965, in Leningrad, Russia. Kadamovas lived in Sherman Oaks, while Mikhel resided in Encino, both neighborhoods in the San Fernando Valley.

In October 2001, Jurijus Kadamovas and his accomplice Iouri Mikhel planned to kidnap Meyer Muscatel, a 58-year-old real estate developer. They lured Muscatel to Mikhel's house in Encino under the pretense of a business meeting. Once there, they restrained, assaulted him, and took his valuables. After they could not access his bank account, they injected him with a drug and suffocated him. They then transported Muscatel's body to New Melones Lake and disposed of it by throwing it off Parrotts Ferry Bridge.

In December 2001, they targeted Rita Pekler, a 39-year-old financial advisor who was pregnant. Kadamovas contacted her, pretending to be interested in real estate. When she arrived at his home, she was ambushed by Mikhel and two other accomplices. After restraining her, they demanded she contact her boss, George Safiev. When he could not help, they killed Pekler by injecting her with the same drug and strangling her. Her body was also dumped in the lake.

Later in December, the duo kidnapped Alexander Umansky, a 35-year-old automobile shop owner. They pretended to need audio equipment and lured him to Kadamovas' home. Umansky was held for three days during which they issued a ransom note asking for $235,000. After receiving the ransom, they killed him in a similar manner, pinning him down and strangling him. His body was taken to the lake and discarded.

In January 2002, Kadamovas and Mikhel set their sights on Safiev through his business partner, Nick Kharabadze. They lured Kharabadze to their aquarium store and captured him. After forcing him to contact Safiev, both were taken to Kadamovas' house. They ordered Safiev to secure a transfer of $940,000. After receiving the money, they killed both men by suffocation at the reservoir, disposing of their bodies in the same way as the previous victims.

Muscatel's body was discovered by fishermen, initiating an investigation. One of their accomplices later cooperated with the FBI, leading to the recovery of the other bodies. Evidence gathered linked Kadamovas and Mikhel to the crimes, including recorded discussions about ransom money and video footage of ATM withdrawals from the victims' accounts.

They were arrested and indicted on multiple counts. Their trial began in 2006 and lasted several months. On January 17, 2007, they were found guilty and sentenced to death for their crimes. Their other accomplices received varying sentences for their roles in the kidnappings and murders. Both Kadamovas and Mikhel were on death row awaiting their execution, until both were among the 37 individuals whose death sentences were commuted to life imprisonment by President Joe Biden on December 23, 2024.