The trial of a Russian accused of killing a Skyguide air traffic controller had begun in Zurich, with the prosecutor demanding a 12-year sentence for murder.
The victim was on duty during a mid-air collision between two jets in Swiss airspace in 2002 in which the defendant's wife and two children died.
Vitaly Kaloyev faces between five to 20 years in prison if found guilty of premeditated killing. Swiss law ranks the charge behind murder but ahead of manslaughter.
The victim, a 36-year-old Dane, was stabbed to death in front of his wife at the family home near Zurich on February 24, 2004.
The prosecutor said that the Russian architect had planned his act well before carrying it out.
"He pursued his goal tenaciously, filled with hate, and killed his victim with extreme brutality," added Ulrich Weder, pointing out the accused had methodically got rid of the knife he used and his blood-spattered clothes.
The Russian's defence team pleaded for manslaughter and said the defendant was tormented by great psychological distress at the time of the crime. They said any prison term should not exceed three years.
"Kaloyev accepts that he killed [the controller]," his attorney Markus Hug told swissinfo earlier. "But we will argue that he was not in a fit state of mind at the time."
Hug also said he was not worried by psychiatric reports which concluded that Kaloyev was responsible for his actions at the time of the alleged murder. These reports did however point to a diminished responsibilty.
For the prosecutor, this was the only reason for demanding a 12-year sentence instead of an 18-year one. "He is a broken man," admitted Weder.
The trial is being closely followed in Russia, especially in Bashkortostan and North Ossetia, where most of the crash victims, including Kaloyev's family, came from.
On Tuesday, about a dozen people picketed the Swiss embassy in Moscow, demanding that Skyguide be prosecuted. They also urged clemency for Kaloyev.
"Skyguide is Switzerland's Shame," one placard read. Protesters also held pictures of children killed in the crash.
In a poll of 1,373 readers, 69 percent of Russians said they supported Kaloyev's acquittal and 31 percent said they considered him guilty, the daily Izvestia said.
The president of North Ossetia has also travelled to Zurich for the court case to support his fellow citizen.
"All the republic understands the grave accusations against him, but we believe that Swiss justice will be fair," said Taimuraz Mansurov shortly before leaving Moscow.
The case is not being heard before a jury as Kaloyev does not deny the killing. Written testimony has been given but no witnesses are present.
The controller was working the nightshift on his own in Skyguide's Zurich operations centre when a Russian passenger jet and a DHL cargo plane collided in mid-air on July 1, 2002, on his watch.
All 71 people on board were killed, including Kaloyev's family and 40 schoolchildren, who were on their way to Spain.
The crash took place over the southern German town of Überlingen in Swiss airspace.
In February last year, Kaloyev was arrested at a hotel in Kloten not far from the Dane's home a day after the man was found dead.
The Zurich public prosecutor's office announced earlier this year that the Russian would stand trial after he admitted visiting the controller's home, looking for an apology. Kaloyev said he "lost control" and "probably" killed the Skyguide employee.
The 49-year-old from North Ossetia said he could not remember exactly what had happened on the night of the attack. He allegedly tried to show the controller photos of his family, which the Skyguide employee knocked out his hands.
After that Kaloyev says he cannot remember anything. The controller was stabbed 20 times with a pocket knife while lying on the ground, bleeding to death.
The Skyguide employee had lived in Switzerland since 1995 and was the father of three children.
Three months after his death, Germany's Aircraft Accident Investigation Bureau partially blamed the controller for the crash.
The prosecutor's office is still investigating the crash, and has so far indicted eight Skyguide employees for manslaughter.
swissinfo, Matthew Allen
July 1, 2002: a Bashkirian Airlines passenger jet collides with a DHL cargo plane, killing 71 people.
February 24, 2004: a Skyguide air traffic controller is stabbed to death.
February 25, 2004: Russian architect Vitaly Kaloyev, whose wife and two children died in the crash, is arrested by police.
February 2005: Swiss prosecutors announce that Kaloyev will stand trial for murder.
October 2005: Kaloyev goes on trial. A verdict is expected on October 26.