ARLINGTON, Va. — Two hotly contested races for commonwealth's attorney in Northern Virginia ended with incumbents losing their re-election bid Tuesday night.

Steve T. Descano narrowly won the race for Commonwealth's Attorney in Fairfax county against incumbent Raymond F. Morrogh..

Challenger Parisa Dehghani-Tafti defeated incumbent Commonwealth's Attorney Theo Stamos in one of the more closely watched races of Tuesday's primary. That district serves Arlington and Falls Church.

Both Descano and Dehghani-Tafti  ran on campaigns of criminal justice reform.

Political experts and commentators noted a late infusion of case into their respective races from the Justice and Public Safety PAC, which records show is predominantly funded by Democratic donor and billionaire, George Soros.  

Both candidates clinched their races narrowly.

Initial tallies showed both candidates won their respective races with 51 percent of the vote.

The Washington Post reported Soros, as a criminal justice reform activist, views prosecutor races as "one of the most direct routes to changing policy because the local offices wield wide power over who gets charged, what charges they face and who goes free on bond."

The contests have also been billed as a "barometer for how far and how fast voters in left-leaning jurisdictions want to push for criminal justice reform," per the Washington Post.

A commonwealth's attorney is the elected prosecutor of felony crimes in Virginia. In most states, the job is referred to as a district attorney or in Maryland, a state's attorney.

LINK: See full election results here

"I am humbled and honored at the trust the voters of Arlington and the City of Falls Church have placed in our campaign," Dehghani-Tafti tweeted. "This election wasn’t about me but about the community’s recognition that criminal justice reform is one of the civil rights issues of our time."

Dehghani-Tafti went on to thank Stamos for her years of service and said she is looking forward to working with her as they move towards the general election later this year.

"Arlington and Falls Church stand ready to show the Commonwealth and the country what it means to put justice back in the criminal justice system," Dehghani-Tafti said. 

Stamos held the position of Arlington's Commonwealth Attorney for the past seven years.

So far, there has not been a Republican challenger in either race.

In Prince William County, the longtime top prosecutor, Paul Ebert did not seek re-election. Amy Ashworth won the Democratic nomination there on Tuesday.

She is a criminal prosecutor and has been working at the Office of the Commonwealth's Attorney for Prince William County since 2005.

Ashworth said in a statement Tuesday night she was humbled and honored to have won the nomination.

"The voters of this community have shown that they are ready for drastic and lasting change in our Commonwealth’s Attorney’s office," she said. "I look forward to continuing the work we’ve started and bringing real criminal justice reform to our jurisdiction.”