LOWELL — An Army veteran under treatment for post-traumatic stress disorder was accused Monday of assaulting his infant son, who authorities say is not expected to survive.
Christopher Berry, who served a tour of duty in Afghanistan, pleaded not guilty and was ordered held on $500,000 cash bail. On several other pending cases, including a domestic incident involving his son’s mother, bail was revoked.
Berry, 22, was alone with his 2-month-old son Saturday in their Lowell apartment when the injuries occurred, prosecutors said. Berry called 911 when he found his son limp and unresponsive, with blood bubbling from his nose and mouth.
At the hospital, the infant was diagnosed with subdural hemorrhaging and a skull fracture.
Prosecutors said they will pursue more serious charges against Berry if the child dies of his injuries. On Monday, the child remained in critical condition at Tufts Medical Center in Boston.
“His prognosis is extremely poor,” prosecutor Katharine Folger said. Even if the baby survives, he will “never breathe on his own,” she said.
When questioned by police, Berry at first said he did not know what had happened to his infant son, how he suffered the massive brain injuries. But when pressed, investigators said, his story changed, and he eventually confessed to shaking the infant.
According to police, Berry said he had accidentally dropped the boy as he lifted him out of a baby swing, causing him to land on his head. But investigators told him that scenario did not explain the “catastrophic injury” his son had.
After asking for a cigarette, Berry told police he had shaken the baby with both hands for 30 seconds, causing the baby to lose consciousness. He sometimes got “stressed” with the baby, police reported.
Berry was advised of his Miranda rights before the interview, police said.
Berry’s lawyer, Robin Gagne, said Berry had served more than three years in the military, and now serves in the National Guard. He is being treated for anxiety, she said.
While in Afghanistan, he was in a vehicle targeted by a suicide bomber, the Lowell Sun has reported.
Gagne argued for low bail, saying Berry had grown up in nearby Billerica and was not a flight risk.
But prosecutors said Berry already faced several other charges, including breaking and entering and animal cruelty. In 2011, Berry allegedly used bird seed to attract a group of pigeons, then ran them over, the Lowell Sun reported.
Neighbors in the apartment complex said they often heard fighting from the home, with sounds of things being broken and a woman’s cries. “I hear banging, yelling, and fighting all the time,” one neighbor said.
According to a police report filed in Lowell District Court, Berry was looking after the baby while his girlfriend was at work. He left the baby in his swing and took a nap, but awoke when he heard the child crying. When he picked him up, the baby “went limp,” he told police. Berry said he first called his girlfriend, but called 911 when she did not answer.
He told police the baby had rolled off the couch the week before, landing face-first. When police told him it was unusual for a baby that young to roll, he replied, “He did.”
“During our conversation, Berry appeared emotionally detached from the child, at times appearing angry with the baby for ‘spitting up’ and ‘pooping,’ ” police stated.
When investigators pushed for more answers, Berry told police “something did happen that he hadn’t told anyone.” He then described how he had accidentally dropped the baby, saying the infant had arched his back and pushed himself out of his grasp.
Police then consulted with a doctor, who said the infant’s injuries would have required “much more force” than a fall, and were consistent with being shaken. Police told Berry “we were only looking for the truth.”
Globe correspondent Matt Rocheleau contributed to this report. Peter Schworm can be reached at schworm@