Unable to locate any record of voter registration notices between Maine and New Hampshire, state authorities have dismissed a complaint involving the son of Republican House Speaker William O'Brien.

The complaint was actually filed against O'Brien's wife, Roxanne O'Brien, one of the supervisors of the checklist in Mont Vernon. The New Hampshire attorney general investigated a complaint that Mrs. O'Brien failed to remove her son — Brendan O'Brien — from the Mont Vernon voter checklist in 2009.

New Hampshire Republicans have passed toughened voter registration laws that require voters to show photo IDs at the polls. Democrats has questioned how Speaker O'Brien could advocate for such laws when his son's voter registration has been called into question.

In 2009, the younger O'Brien registered to vote in Lewiston, Maine, where he attended college. The following June, he ran unopposed in a Republican primary there.

Book-ending that time period, Brendan O'Brien voted in Mont Vernon in the November general elections in 2008 and 2010. Investigators found no evidence that he voted in the Maine 2010 general election.

As part of the investigation, Mrs. O'Brien told the Attorney General's Office she didn't remember when or how she found out about her son's candidacy in the Maine primary. But she told investigators she had his name removed from the Mont Vernon checklist in 2011 when her son showed her his Maine driver's license.

“It is hard to believe that Speaker O'Brien and his wife — the Mont Vernon supervisor of the checklist — did not know where members of their own family were living or that they were running for office there,” said Collin Gately, spokesman for the New Hampshire Democratic Party.

But Republican leaders blasted such criticism, and in a release Monday accused state Democrats of trying to drag the O'Brien family through the mud.

“Attacking the families of elected leaders to gain political points truly speaks to the worst of what turns people off from public service. There is no place for this type of behavior by the New Hampshire Democrat Party and their friends in public discourse,” said Deputy House Speaker Pam Tucker.

Last week, Associate Attorney General Richard Head notified Mrs. O'Brien's lawyer that the investigation was closed.

When a voter registers in a new community, election officials typically notify officials in his former place of residence about his new registration so the voter is not registered in two communities.

But no record of such notification could be found. In Lewiston, City Clerk Kathy Montejo told investigators the city had upgraded its computer system since 2009, and she could find no emails to New Hampshire or Mont Vernon officials about Brendan O'Brien. She said it's possible a notice was never sent to New Hampshire.

In New Hampshire, the Secretary of State's Office told investigators that it does not keep a record of the hundreds of postal and email notices it receives about changed registrations. It just forwards them to election officials in the proper communities.

In Mont Vernon, officials told investigators they had no documentation of any registration change for Brendan O'Brien, either from Maine or New Hampshire officials.

“Based upon the information available, there is insufficient evidence to determine whether Maine ever notified either the town of Mont Vernon or the New Hampshire Secretary of State's Office that Mr. O'Brien was registered to vote in Maine,” Head wrote.

mhayward@unionleader.com