A serial killer nurse who admitted killing 29 patients donates one of his kidneys to the brother of an ex-girlfriend.

Charles Cullen had threatened to skip his sentencing hearing if he was not permitted to be the donor.

In February, a judge approved Cullen's removal from prison for the operation.

Cullen's public defender, Johnnie Mask, says the kidney went to Ernie Peckham, 37, of Rocky Point, New York.

Mask tells The Associated Press, "They have not had a chance to speak" since the operations on Aug. 20.

One day after surgery, Cullen went back to New Jersey State Prison. Peckham did not return to his Long Island home for a few days.

The New York Daily News reports Peckham is married with four children. He is a metalworker and Cub Scout leader who was an Army reservist.

Peckham told The Village Beacon Record that his kidneys began failing after a cut on his finger became a strep infection.

Cullen confessed to using drug overdoses to kill 29 patients at nursing homes and hospitals in Pennsylvania and New Jersey.

He was sentenced to 18 life terms in prison.