Fairfax County police are investigating the death of a 53-year-old woman at the county’s jail.

The woman suffered a medical emergency in her cell on Aug. 31 and was taken to the hospital, where she was pronounced dead on Thursday, police said.

The Fairfax County Sheriff’s Office, which runs the jail, said in a news release that a sheriff’s deputy called a medical emergency for the woman around 7 p.m. on Aug. 31 after she suddenly became ill.

The woman was transported to Fairfax Hospital, where she was pronounced dead shortly after 11 a.m. on Thursday, police said.

The Sheriff’s Office and police did not immediately identify the woman or offer details about the nature of her medical emergency. The police investigate all in-custody deaths at the jail.

The death is the third at the jail this year. Fairfax County police are also investigating the deaths of inmates, who were found unresponsive in August and April, police said.