A young Standish father indicted on charges of murder and manslaughter for the death of his infant son last year pleaded not guilty to both charges Wednesday during a brief court appearance.

Eugene “Charlie” Martineau, 24, is accused of shaking 3-month-old Leo Josephs with enough force to cause his head to “snap back and forth” and later trigger a fatal seizure, according to an affidavit unsealed in the Cumberland County Courthouse in Portland after his arraignment.

Martineau appeared with his attorney, Clifford Strike, in the courtroom before Justice Andrew Horton and entered pleas of not guilty to both charges. Horton ordered Martineau’s bail to remain at $150,000 cash, and Strike reserved his right to request a bail hearing at a later date. Martineau has been held since his arrest in October at the Cumberland County Jail.

Main State Police were first called in on the evening of Oct. 21, 2015, to Maine Medical Center in Portland, where the baby had been admitted in critical condition and later died on Oct. 24 as a result of injuries from being shaken and the seizure, according to the affidavit by state police Detective Lauren Edstrom.

Edstrom interviewed Martineau twice in the days before the baby died, and Martineau confessed to her, the affidavit states.

“He was crying at the start of the (Oct. 22) interview. When I asked him why he was crying, he replied, ‘Because I hurt my son,’ ” Edstrom wrote in the affidavit. “Martineau went on to describe how frustrated he would get when baby Leo would cry. He described the crying as ‘obnoxious.’ Martineau stated he would push down on baby Leo(‘s) chest to get the air out to make him stop crying. He said he did this three to four times because he ‘couldn’t handle it.’ ”

Martineau, the baby and the baby’s 21-year-old mother Julia Josephs had been staying in a room at a multifamily house on Bonny Eagle Road in Standish at the time Martineau is accused of shaking the baby. They had been living there with their dog and 12 other people and two other dogs, according to the affidavit.

Leo and his twin sister, Leah, were born prematurely on July 2. The girl remained at Maine Medical Center because of complications from the early birth, but Leo was released at the beginning of August.

“Martineau admitted to shaking baby Leo,” Edstrom wrote, describing her Oct. 23 interview. “Martineau said he got frustrated, held baby Leo in front of him and shook him. He said he watched baby Leo’s head snap back and forth. He said baby Leo stopped crying but he ‘regretted it instantly.’ ”

If convicted of murder by depraved indifference Martineau faces 25 years to life in prison. If convicted of manslaughter, he faces up to 30 years in prison.

Scott Dolan can be contacted at 791-6304 or at:

[email protected]

Twitter: @scottddolan