A subpoena has been issued by the city Board of Ethics as it looks into who is behind two so-called 527 committees that have surfaced in the Philadelphia mayor's race.

Alex Z. Talmadge Jr., former city commissioner and executive director of a committee called the Economic Justice Coalition for Truth, said today he had been subpoenaed by the ethics board. The subpoena was dated Monday and hand-delivered to his law office; he said he did not see it until yesterday.

He said he was surprised because "I don't know of anything we have done that would elicit a subpoena from them."

"They want to see everything we have - the expenditures and disbursements we've made, the contributions," Talmadge said. "I have no problem with that. We've collected money and made minor expenditures. . . . They can explore whatever they think necessary."

Talmadge said his group would be filing a campaign finance report on Friday, as required by state law.

The group aims to air TV ads bashing mayoral candidate Tom Knox. It laid out $35,000 this morning to purchase time for ads that are to air tomorrow and Friday, TV station records show.

That ad was produced by political consultant Ken Smukler, Talmadge said. Smukler left Bob Brady's mayoral campaign last week amid controversy over Smukler's admitted efforts to get others to start a 527 committee.

Smukler has said he produced the new anti-Knox ad on his own.

Knox, a millionaire businessman, has been a front-runner in polls of the May 15 Democratic primary race. Talmadge has backed Brady - who, along with Talmadge, has denied any coordination between the 527 committee and the Brady camp.

Federal law makes such coordination unlawful for 527s, nicknamed for the section of tax law that authorizes them. The ethics board is conducting an initial inquiry into whether the 527s run afoul of the city's caps on campaign spending. Those caps, among others things, limit a candidate to one campaign fund-raising committee.