An Albanian court acquitted two senior police officers on Thursday of shooting dead four opposition supporters during an anti-government protest in 2011.
The ruling was bluntly criticized by the United States, which provided assistance in the forensic investigation, and was met with outrage by Albania's political opposition, fueling the country's rising political tensions ahead of its June 23 general election.
The Socialist opposition party walked out of Parliament in protest Thursday, and the son of one of the dead hinted that relatives could take the matter into their own hands in accordance with Albania's long history of vendettas.
"Tradition says that blood is paid with blood," the son, Renato Myrtaj, told the private News 24 television station.
Presiding judge Besnik Hoxha said prosecutors were unable to prove the charges against Ndrea Prendi, head of the elite Republican Guard, and Agim Llupo, a senior officer in the unit. A third officer was acquitted of concealing evidence about the Jan. 21, 2011, shootings.
Prendi and Llupo were charged with the murder of Faik Myrtaj, Hekuran Deda and Ziver Veizi; no one has been charged in the death of the fourth protester, Aleks Nika.
An investigation found that police bullets killed four men at a Socialist Party protest against alleged corruption and vote-rigging by Prime Minister Sali Berisha's government. Prendi and Llupo admitted firing shots in the air, but denied hitting anyone.
Berisha declined to respond to the ruling Thursday, saying he would never "comment on a court verdict."
The opposition has accused Berisha of authorizing police to use lethal force at the protest - a claim the prime minister rejects.
"I assure the families of the four martyrs that their deaths cannot be forgotten ... until a fair verdict is obtained," Socialist Party leader Edi Rama said.
"When justice speaks, you should keep silent," responded Parliament Speaker Jozefina Topalli, a governing Democratic Party lawmaker.
A spokesman for the Prosecutor General's office, Albi Serani, declined to say whether prosecutors would appeal the ruling. He said they must read the decision first.
The U.S. Embassy in Tirana issued a statement saying it was "dismayed" by the court decision.
The court did not take into consideration "extensive assistance, including expertise from the world-class Federal Bureau of Investigation Crime Lab," provided by the United States after an urgent request from the Tirana government and the Prosecutor General's office.
"Today's verdict has undermined confidence in the ability and willingness of the Albanian judicial system to deliver justice in an impartial, transparent manner," the embassy said.