A New Bedford man has pleaded guilty to robbing a bank in Dartmouth while on supervised release after serving a prison sentence for another bank robbery.

David A. Frates, 43, pleaded guilty yesterday in Boston federal court to one count of bank robbery, according to a statement from the U.S. attorney’s office. Frates had been charged on Oct. 7.

According to the statement, Frates had entered a Bristol County Savings Bank branch in Dartmouth on July 19, 2021. Frates then approached a teller, demanded $20,000 and threatened to stab a second teller if his demands were not met, the statement said.

Frates then produced a long-handled knife and repeatedly struck the knife on the teller’s counter, saying he was going to stab the teller, according to the statement. The teller handed Frates $20,000 from the bank’s vault, and Frates exited the bank.

Law enforcement identified Frates as the robber and arrested him two days later. At the time of his arrest, Frates was in possession of over $9,000 in cash, the statement said.

Frates had been convicted in 2014 on federal bank robbery charges for the armed robbery of a St. Anne’s Credit Union branch in New Bedford and received an 11-year prison sentence. The prison sentence was reduced in May 2020 to 81 months based in part on changes in the United States sentencing guidelines, the statement said.

Frates’ sentencing for the Dartmouth robbery is scheduled for July 13.

In a separate case, a Brockton man was charged in Boston federal court last week with robbing an Eastern Bank branch after law enforcement used fingerprints from another bank robbery to identify a suspect.

Nathon Caeser Ribeiro Neves, 22, was charged on March 4 by criminal complaint with one count of bank robbery, according to a statement from the U.S. attorney’s office.

According to the charging documents, a masked individual, later identified as Ribeiro Neves, entered Eastern Bank’s Lakeville branch on Nov. 8, 2021. Ribeiro Neves allegedly passed a teller two demand notes indicating a robbery and that “a bombing would happen if no payment was made.”

The teller gave Ribeiro Neves cash from her drawer, the statement said, and Ribeiro Neves exited the bank leaving the demand notes behind. The notes were later determined to contain fingerprints.

A week later, Ribeiro Neves allegedly robbed a Cornerstone Bank branch in Worcester and was arrested by law enforcement a few minutes after the robbery, the statement said. According to the charging documents, law enforcement obtained Ribeiro’s fingerprints, which were found to match the prints from the demand note in the Lakeville robbery.