Nemtsov was shot multiple times while walking near the Kremlin.
On his Twitter feed, Rinkevics said:
Horrible news of the murder of Boris #Nemtsov, condolences to family, Russia must conduct swift, non partial investigation, provide answers
— Edgars Rinkēvičs (@edgarsrinkevics) February 27, 2015
Nemtsov, 55, had visited Latvia several times in recent years as part of his opposition activities.
Lithuanian Foreign Minister Linas Linkevicius expressed similar sentiments:
Deeply sad when voices of democracy get killed in Russia. RIP Boris Nemtsov, heartfelt condolences to family. Your battle will continue.
— Linas Linkevicius (@LinkeviciusL) February 27, 2015
Estonian Foreign Minister Keit Pentus gave an equally strong message:
Hard to find words. Awful and cowardly murder. Shocking. Deepest condolences to the family of #Nemtsov and to all democrats in Russia.
— Keit (@KeitPentus) February 27, 2015