Black Lives Matter activist Sasha Johnson is in critical condition after being shot in the head, her political party said in a statement. The British activist was shot in London on Sunday (May 23).

“It is with great sadness that we inform you that our own Sasha Johnson has been brutally attacked and sustained a gunshot wound to her head,” Britain’s Taking the Initiative Party said. “She is currently in intensive care and in a critical condition.”

According to the party, Johnson was attacked “following numerous death threats as a result of her activism.”

London’s Metropolitan Police also released a statement and said officers responded to reports of gunfire in southeast London around 3 a.m. local time on Sunday morning. Paramedics then transported a 27-year-old woman, later identified as Johnson, to a south London hospital where she was treated for gunshot wounds. Police also said the shooting appeared to have happened near a house party in Southwark.

Officials said it was too early in their investigation to determine whether or not Johnson “had received any credible threats against her.” According to the statement, the shooting is being investigated by Met’s Specialist Crime Command (Trident) and detectives are looking to speak to any witnesses who were attending the party.

“A dedicated team of detectives is working tirelessly to identify the person or persons responsible for this shooting,” Detective Chief Inspector Jim Tele said, adding that “they need the public’s help” in learning more about the incident.

Tele also acknowledged that while the attack on Johnson “will have shocked those in the local community and further afield,” he encouraged the public to “avoid speculating as to the motive or the circumstances behind it.”

Johnson is a well-known Black Lives Matter advocate who rose to prominence attending protests last year. She’s also the founder of the Taking the Initiative Party, which has been described as “Britain’s first Black-led political party.”

In a statement, Black Lives Matter UK said it would hold a vigil for Johnson on Monday (May 24) outside of King’s College Hospital. The organization hailed Johnson as a “young mother and fearless political campaigner who was at the forefront of many BLM protests last summer.”

The organization also said Johnson regularly delivers food and groceries to needy families and called her “a strong, powerful voice for our people and our community.” See Black Lives Matter UK’s tweet about the vigil below.