Dallas County Elections Administrator Bruce Sherbet says clerical errors by his department are to blame in two cases of questionable voting activity Texas Watchdog wrote about Thursday.

In this video report, Sherbet showed WFAA-TV the sign-in records for voter Howard Ingram's polling place in March 2008. The records showed a stamp by the Foley Street resident's name that was later crossed out. Ingram passed away in 2006.

So even though Ingram is listed in the department's electronic records as voting in March, Sherbet says that's a mistake. Sherbet said a clerical error also explains why Melvin Porter, who died in 2007, was listed in electronic records as voting in March.

"I can tell you with 100 percent certainty no one signed in those voters and voted," Sherbet told the station. "It was a clerical error."

Our initial story raised the possibility of such recordkeeping mistakes.

We plan to check polling place records for the dozens of other dead voters whose records show ballots cast after their deaths. A department official said he'll help us go through the books after Election Day. More about that in Thursday's blog post.