CONCORD, N.H. – Authorities confronted with a recent spike in bank robberies say they have found the cause – two brothers from the Concord area. They have been charged with robbing a dozen banks stretching from Stratham to Conway during a three-month period.

Travis Blodgett, 26, and Avery Blodgett, 24, were arrested Jan. 23 in Sweden, Maine.

A federal grand jury indicted Avery Blodgett on seven counts of bank robbery, one count of conspiracy to commit bank robbery and two weapons charges. Travis Blodgett faces 10 counts of bank robbery and one charge of conspiracy to commit bank robbery.

The maximum sentence for bank robbery is 20 years. Armed bank robbery carries a maximum 25-year sentence.

“The message that we have here today … is that New Hampshire is not a place for someone to commit bank robberies, unless they want to go away to prison for a very long time,” U.S. Attorney Thomas Colantuono said Thursday at a news conference.

With the arrest of the Blodgetts, there are no New Hampshire bank robbery fugitives at large, he said.

The recovery of a stolen car in Laconia cracked the case, Colantuono said. He would not give specifics.

Authorities have not recovered the nearly $86,000 the brothers allegedly stole during the October to January spree. They suspect part of the money was used to buy drugs; police said they found cocaine while searching the suspected getaway car.

The brothers were being held at the Strafford County jail.

Colantuono said the Blodgetts were suspected of committing nearly half the 28 bank robberies committed in New Hampshire since October 2005.

“This is a dramatic increase from the past,” he said.

The average has been 20 bank robberies a year for the last five years, he said.