An Augusta man suspected of holding up a Hallowell bank last month is in federal custody.

John Cecil Slater, 66, is scheduled for a hearing at noon Thursday in U.S. District Court in Bangor on a charge that he robbed the Bank of Maine on Winthrop Street on June 23.

It was not immediately clear where Slater was arrested.

Investigators had been seeking the public’s help in finding Slater, whom they described as armed and dangerous.

Documents unsealed following Slater’s arrest show investigators located the note used in the bank robbery in Slater’s apartment in Augusta.

The note said, “Im Here to Rob your Bank, no silent Alarms my cell Phone rings, your all dead, I have a hand grenade, and a gun, no marked bills, or inked, if so, one day I will come back and kill all of you, do you understand.???”

Along with the random capitalization, several words were underlined.

The text was included in an affidavit filed in federal court by FBI Special Agent Glenn D. Barnes.

The affidavit says the robber fled the bank with $15,000 in $100 bills.

Slater, who as an extensive criminal history, was later identified as the suspect through surveillance photos from the bank.