Prosecutors say the victim, a California tourist, was attacked while changing her 10-month-old daughter on the store’s seventh floor.
NEW YORK — A Massachusetts woman was ordered held without bail Friday after police say she stabbed a California tourist in the back and arm while the victim was changing her baby’s diaper inside the women’s restroom at Macy’s Herald Square on Thursday afternoon.
Authorities identified the suspect as Kerri Aherne, 43, of Tewksbury, Massachusetts. The attack happened just before 3 p.m. on the flagship store’s seventh floor, officials said. The 38-year-old mother was hospitalized with non-life-threatening wounds; her 10-month-old daughter was not hurt. The case has quickly escalated, with prosecutors describing an unprovoked assault in a crowded holiday shopping hub and laying out an early timeline that includes the suspect’s movements inside the store.
Prosecutors said Aherne walked into the women’s restroom, approached the mother from behind and stabbed her multiple times as the woman tended to her child. During the struggle, the baby fell from the changing table but was examined and found unharmed, according to officials. The victim’s partner helped subdue the attacker until store security detained her. Police later recovered a knife from the scene. In court, prosecutors said Aherne told investigators that “voices in her head” instructed her to kill someone. She was charged with attempted murder, assault, endangering the welfare of a child and criminal possession of a weapon, authorities said.
Court filings state Aherne had a documented psychiatric history and had been discharged from the Manhattan Psychiatric Center on Thursday morning. Investigators say she bought a knife inside the Herald Square store before the attack. The victim, visiting from Southern California, was treated for stab wounds to her back and arm and released in stable condition, officials said. The woman’s partner, who works for a sheriff’s office in Riverside County, California, disarmed the suspect, according to prosecutors. Macy’s said in a statement it was “saddened” by the incident and is cooperating with police.
Records and officials familiar with the case said Aherne has prior arrests and encounters with mental health services in Massachusetts. New York authorities are reviewing her out-of-state history as they assess risk and bail conditions. The store, one of the city’s busiest during December, draws thousands of visitors daily, and police said they increased patrols in and around the building following the stabbing. The Midtown South precinct has seen seasonal crowding that can complicate emergency responses during peak hours, according to officers who work the area.
At Friday night’s arraignment in Manhattan Criminal Court, a judge ordered Aherne held without bail while prosecutors seek grand jury action. Additional hearings are expected next week, prosecutors said. Detectives are collecting surveillance footage from the seventh floor and nearby departments, interviewing store employees and canvassing for witnesses who were in the restroom hallway at the time. Investigators are also tracing the knife purchase and reviewing hospital discharge records as part of their timeline.
By Saturday afternoon, the restroom area remained closed to shoppers while crime scene technicians completed measurements and photographs. Holiday crowds moved past cordoned-off sections on the seventh floor, where parents said they had chosen other changing areas. “It happened in seconds,” a shopper who heard yelling from the corridor said. “Security was there fast, and then the police.” The victim’s family returned to their hotel, according to officials, and requested privacy.
The suspect remains in city custody, and police say more evidence will be presented to a grand jury in the coming days. Authorities said the next court appearance is expected next week as the investigation continues and additional witness statements are gathered.
Author note: Last updated December 14, 2025.