An electoral system with a spotty record, claims of hacking, the mysterious killing of an election official, and the threat of post-election violence makes this week’s presidential election in Kenya one of the most closely watched in Africa.

Adding to the intrigue: The head of the country’s election commission acknowledged Thursday there had been an unsuccessful attempt to hack its database. That acknowledgment came a day after Raila Odinga, a leading presidential candidate, claimed the elections were fixed in favor of the incumbent, President Uhuru Kenyatta.

“Hacking was attempted but did not succeed,” said Wafula Chebukati, chairman of the Independent Electoral and Boundaries Commission (IEBC). His remarks have the potential to raise tensions in a country that already has seen five people killed in post-election violence. Although the results are not final, Kenyatta holds a strong lead over Odinga with most of the votes counted at polling stations.

Calm also appears to have returned Thursday following the tensions sparked by Odinga’s claim, which prompted fears Kenya would descend into the kind of post-election violence that saw more than 1,000 people killed and tens of thousands made homeless a decade ago. That election was widely condemned as flawed. Odinga, 72, was the losing candidate on that occasion, too. (The situation was resolved through a power-sharing agreement.)

Odinga, the son of Jaramogi Odinga, Kenya’s first vice president, was a candidate in the 2013 election, as well. He lost by a wide margin to Kenyatta, 55, the son of Jomo Kenyatta, the country’s first president. That election was mostly peaceful. The latest election is seen as the last opportunity for Odinga to become president. Tensions were high because, among other things, polls showed the candidates neck-and-neck, they are the sons of Kenya’s two long-warring political dynasties, and from rival ethnic communities. All of this risked instability in East Africa’s largest and most vibrant economy, which is also an important Western ally in the war on terrorism.

The trouble with the latest election began when the initial results showed that Kenyatta was comfortably ahead of Odinga despite pre-election opinion polls suggesting a close race. Odinga claimed fraud, saying the IEBC’s database was hacked. What lent his claim a more than conspiratorial edge was the murder of Chris Msando, the acting head of technology at the IEBC. Just days before his body was discovered late last month in a forest outside Nairobi—officials said he was “tortured and murdered”—Msando appeared on national TV to tell Kenyans that election system was secure. Odinga claimed Tuesday that hackers gained entry into Kenya’s election database using Msando’s identity. He declined to reveal the source of his claim, but that didn’t prevent the eruption of violence in which five people were killed.

Despite his acknowledgment Thursday of a hacking attempt, Chebukati, the head of the election commission, said the system hadn’t been compromised. Here’s how that system works: Biometric measures are used to identify votes—in order to avoid fraud—and a results-management system adds the votes once they have been counted at individual polling stations. But this system isn’t foolproof—and has had mixed results when used in other parts of Africa, including, previously, Kenya.

International monitors, though, said the voting process itself was fair, adding any disputes should be resolved through the legal process.

“We affirm the conviction that the judicial process, the judicial system of Kenya and the election laws themselves make full and adequate provision for accountability in this election,” said John Kerry, the former U.S. secretary of state, who was an election observer for the Carter Center. “The streets do not.”

Martietje Schaake, the head the EU’s monitoring team, said there were “no signs of centralized or localized manipulation.” She added the mission “can look into the” allegations of fraud, “but more importantly will look at how the responsible authorities manage the issue.”  

Thabo Mbeki, the former South African president who heads the African Union’s mission to observe the election, praised Kenyans for voting, but added: “It would be very regrettable if anything emerges afterwards that sought to corrupt the outcome, to spoil that outcome.” Mbeki said the AU mission had taken note of Odinga’s concerns, but said his team did not have the mandate to investigate the claims.  

“The IEBC, obviously, together with the parties concerned must conduct that investigation,” he said.

The political unrest comes amid a period of robust economic growth in Kenya. Last year Kenya grew 5.9 percent, a five-year high, according to World Bank data. Kenyatta, who was elected in 2013, made that the centerpiece of his campaign. As Murithi Mutiga, a senior analyst with the International Crisis Group, explained in a briefing paper:

A $3.8 billion Chinese-built railway connecting the port city of Mombasa to Nairobi began operation on 31 May. It is expected to be extended to neighbouring Uganda and Rwanda. The Kenyatta administration has also waived fees in maternity hospitals and expanded electricity coverage in rural areas.

But the economy faces headwinds, too, the World Bank warned in April. Growth in 2017 was expected to dip to 5.5 percent. Odinga’s National Super Alliance said it would provide more economic opportunities to all Kenyans, noting that Kenyatta’s administration was dominated by members of the Kikuyu community, as well as the Kalenjin community of Deputy President William Ruto. Odinga is from the Luo community, and the ICG’s Mutiga points out its “members chafe at years of exclusion from state power. … many voters view him [Odinga] as a champion of marginalized groups in the country.”

If, as expected, Kenyatta is declared the winner, those concerns of marginalization are unlikely to be assuaged. Either way, with the claims of hacking, it’s unlikely the IEBC’s announcement of the final results are likely to be last word on the matter.