Two former assistant district attorneys have joined an increasingly crowded campaign to unseat Philadelphia District Attorney Seth Williams.

Former Assistant District Attorney Michael Untermeyer on Monday announced his candidacy for the Democratic nomination.

A few hours later, Beth Grossman, a 21-year veteran of the District Attorney's Office now in private practice, said she would run as a Republican.

Untermeyer, 65, a real estate developer and businessman, became the fourth challenger to Williams in the Democratic primary May 16. The Rutgers Law graduate ran against Williams in 2009 as a Republican.

"It is time for the top law enforcement official in Philadelphia to set the standard for innovation, integrity, and sound management," Untermeyer said in a statement.

Grossman, 48, who joined the District Attorney's Office in 1993 under Lynne M. Abraham, noted her roots as a fourth-generation Philadelphian and offered as a campaign catchphrase, "Beth Not Seth."

Both candidates have long careers in public service.

As senior deputy in the state Attorney General's Office from 1990 to 2001, Untermeyer headed the asset forfeiture and money laundering section of the Philadelphia office of the drug law division, where he supervised financial investigations and prosecutions of major narcotics dealers and organizations.

Before that, he worked as a prosecutor under then-Philadelphia District Attorney Ed Rendell. He was among the attorneys assigned to then-new Domestic Violence Unit.

Untermeyer said he would like to change Philadelphia's bail system, which allows "suspects of financial means to be released while the poor are relegated to jail for the same or lesser crimes."

He said other cities have developed innovative ways to replace traditional bail systems.

"Let's learn from them and create a better justice system for Philadelphia," he said. The last time he campaigned, he wore an electronic ankle monitoring bracelet to highlight the lower cost vs. imprisonment.

He also proposed curbing fentanyl-laced heroin overdoses resulting in death by charging heroin dealers with homicide, and "zero tolerance" for carrying illegal handguns.

Grossman graduated from Pennsylvania State University and Temple Law School. She made particular reference to a reported federal investigation surrounding Williams' campaign finances.

"Philadelphians deserve better," she said in a statement.

She also said her campaign would "free Philadelphia from the dangerous built-in corruption of one-party rule."

"Like Arlen Specter years ago, I switched parties and have chosen to run as a Republican because democracy only works, at any level of government, when there is a two-party system, when elected officials know they are being watched by a loyal but skeptical opposition," she said.

Grossman served in the trial, juvenile, law, investigations, and narcotics divisions of the District Attorney's Office. In 2007, she became chief of the public nuisance task force, where she worked with communities across the city to address quality-of-life issues, including drug properties, nuisance bars, and littered and vacant lots.

Dan Fee, campaign spokesman for Williams, was dismissive of both new candidates.

"It's hard to keep up with the Democrats becoming Republicans and Republicans becoming Democrats," he said. "One thing is clear: None of them have been able to say what they would have done differently or better as DA. Seth is proud of his record, which includes winning national grants for innovation and reform, and looks forward to detailing his successes for the people of Philadelphia through the spring."

Untermeyer and Grossman join former Philadelphia Managing Director Rich Negrin, former Assistant District Attorney Joe Khan, and Municipal Court Judge Teresa Carr Deni in the race against Williams.