A jury found him guilty on Monday, the former construction worker accused of murdering nine people, a case that had terrorized the population in the Phoenix area, Arizona, in the summer of 2006.
Mark Goudeau was accused of attacking his victims while they were engaged in daily activities, such as preparing a lunch or leaving their desks. The fly of the pants of several bodies had been lowered. The victims, eight were women, were aged between 19 and 39.
This ruling, delivered after four months of trial, allows prosecutors to initiate proceedings to seek the death penalty against Goudeau.
Prosecutors have described the killer as "ravenous wolves", raping women and killing those who do not obey him. Counsel for the accused, aged 47, has insisted that there could be other suspects in the deaths and questioned the credibility of DNA testing links Goudeau to the crimes.
Although the man is already serving a sentence of 438 years in prison for raping a woman while pointing a gun against his sister's womb, prosecutors continued their efforts in nine counts of murder in a separate trial to condemn him to death.
Goudeau has pleaded not guilty to 72 counts brought against him, which also included rape and assault against children.
The killings began in August 2005 and concludes with the murder of Carmen Miranda in June 2006. The mother of two to vacuum his car while talking on his cell phone when a man was kidnapped, was shot in the head and pushed his body in the back seat.
The other eight victims were also attacked at random, but all were shot in the head and left in a pool of blood. A kindergarten teacher at 39 years old, Tina Washington, waiting for the bus after a Christmas party when she was killed. His body was found in an alley, December 12, 2005.