The shootings have been spread across the county.
Although most of the shooting was in Gästrikland, where seven out of twelve shootings took place.
It has been shot in Hofors, Sandviken, Gävle, Österfärnebo, Söderhamn, Ockelbo and Hudiksvall.
In seven of the cases, one or more suspects have been arrested for involvement in a shooting.
Escalating gun violence
During the autumn, violent crimes escalated mainly in Gästrikland and there were several shootings in a short time.
On October 25, a 16-year-old boy was shot to death in Sandviken.
On October 30, several shots were fired at a man at the central station in Gävle.
He was hit in the leg.
On November 5, a man was shot dead on the campus in Sätra in Gävle.
The police called a press conference in connection with the development of events.
- We understand that there is concern in society in view of what has happened, said Catarina Bowall, Gävleborg police area chief at the time to SVT Gävleborg.
Two convicts
In two of the cases, people have been convicted of crimes.
A 19-year-old has been sentenced to 3 years and 10 months in prison for the tunnel shooting in Sätra.
The teenager who posed with a weapon at Bromangymnasiet in Hudiksvall has been sentenced to closed youth care.
Watch SVT's reporter take you through this year's 12 shootings in the videos below:
SVT guides you quickly - here are the shootings in Gävleborg last year
12 shootings in Gävleborg this year
16 sec
February 28, Söderhamn
15 sec
April 6, Hofors
13 sec
April 16, Sandviken
10 sec
April 23, Sandviken
10 sec
June 6, Hudiksvall
14 sec
June 11, Hudiksvall
9 sec
August 7, Ockelbo
12 sec
August 17, Gävle
15 sec
August 5, Österfärnebo
17 sec
October 25, Sandviken
10 sec
30 October, Gävle
12 sec
November 5, Gävle
16 sec