FAIRFIELD — A 19-year-old is in custody after he allegedly beat his girlfriend so badly he left her with a concussion and bruises around her neck.

Christian Ghiorzi was picked up at his Pope Street home around 4 a.m. Friday and charged with second-degree assault, second-degree strangulation, second-degree unlawful restraint, first-degree reckless endangerment and disorderly conduct.

The former Fairfield Ludlowe High School athlete was originally held on a $25,000 bond and was arraigned Friday at state Superior Court in Bridgeport, where his bond was upped to $125,000. After making bond, Ghiorzi was fitted with an ankle monitoring bracelet and was ordered to have no contact with the victim.

If convicted, Ghiorzi, who ran track and played football at Ludlowe, faces up to five years in prison for each of the assault and strangulation charges, both class D felonies.

Police are still trying to piece together the details of the incident because the victim, also 19, lost consciousness in the ambulance on the way to St. Vincent’s Medical Center.

Officers were called to the victim’s home by her parents. The victim’s face had “massive swelling” and she had multiple injuries to her face, lips, neck, chest and upper arm. There was dried blood around her nostrils and her left earlobe and bruising around her neck, according to the report.

Police said Ghiorzi and the victim went with some friends to Stamford Thursday night, and returned to Fairfield by train. From the Fairfield Metro Center, they went to a friend’s house on Dogwood Lane, but the couple left there and were apparently on their way to Ghiorzi’s house. When they left Dogwood Lane, friends said, the couple appeared fine and were not arguing.

Officers who went to Ghiorzi’s home said he immediately answered the door and after a brief conversation, he was issued the Miranda warning. At that point he told police, “I want to exercise the right to an attorney before I talk about anything.”

The incident is being investigated by detectives from the domestic violence unit.