An unidentified person on Tuesday allegedly attacked three minor Dalit sisters with acid in a village in Uttar Pradesh’s Gonda district while they were asleep in their home, The Indian Express reported.

The eldest sister, who is 17-years-old, suffered 35% burn injuries. The younger ones, aged 12 and 8, sustained 25% and 5% burns, respectively. They are hospitalised and are said to be in a stable condition.

The attacker is said to have entered the girls’ room through the terrace at 2 am, according to NDTV. Their father rushed to the room on hearing screams but the suspect had fled by then.

Gonda Superintendent of Police Shailesh Kumar Pandey told the news channel that the family has not named a suspect. “Hence, the investigation is being done based on a complaint against unknown persons,” he said. “However, we suspect that a known person has a role in this.” The crime scene was also searched by the forensic teams and a dog squad, according to The Indian Express.

The girls’ father, who irons clothes for a living, said that they had fixed the eldest sister’s wedding. “Her face has been burnt because of the acid,” he told NDTV. “Now I don’t know how the wedding will happen.”

Congress leader Priyanka Gandhi Vadra, who has been criticising the Uttar Pradesh government for its handling of the Hathras gangrape case, expressed outrage over the incident. “This man’s three daughters aged 17, 10 and 8 were asleep in their home when someone entered and threw acid on them,” she tweeted with a video of the girls’ father speaking to the media. “The UP government’s politically motivated narrative of justifying and protecting perpetrators of crimes against women has only emboldened criminals across the state.”