In May 1999, Egils Barkans, 27, shot dead two plain-clothes police officers and injured two more when they entered his home in the vicinity of Balvi, eastern Latvia, without the necessary warrants.
Police said after the incident that they had gone to investigate a claim that alcohol was being illegally produced or traded at Barkans' home.
An Interior Ministry investigation later found no illegal alcohol on the premises and failed to prove Barkans' involvement in any illegalities pertaining to trading alcohol.
A lower court acquitted Barkans, but after prosecutors appealed Latvia's Supreme Court sentenced him to three years in prison for manslaughter.
Following the shooting, former Interior Minister Roberts Jurdzs disciplined the Balvi district police chief as well as the criminal police chief.
Presidential spokeswoman Aiva Rozenberga told The Baltic Times Vike-Freiberga had not issued a statement explaining her decision to pardon Barkans.
Rozenberga said, however, that in addition to her regular advisers the president had consulted prison officials and Barkans' family.
The president's advisers decided Barkans had shot the officers in a state of temporary insanity.
The Latvian president has the right to issue pardons not on her own initiative but on receipt of an appeal from a convicted person.