On 6 August 2011 a 62-year-old employee was killed at the site.
She then shot and killed six employees of the plant with a pistol before taking her own life.
They killed three employees and wounded another during the winter of 1862-63.
Three employees were killed over the last few months in various shooting attacks.
Two employees were killed in the assault and three injured.
One employee was killed while four others were treated for injuries.
Four off-duty employees have been killed in the last two years.
The one other Christian employee of the paper was kidnapped and killed.
Two Palestinian employees of the refugee agency have also been killed.
It followed a day of violence during which protesters set fire to a bank, killing three employees.
