Ana Cumpănaș or Anna Sage, nicknamed Woman in Red (1889 – April 25, 1947), was a Romanian prostitute and brothel owner in the American cities of Chicago and Gary, Indiana. She is best known for assisting the Federal Bureau of Investigation to track down gangster John Dillinger.

Cumpănaș was a native of Comloșu Mare, a village in the Banat region of what is now Romania. She married Michael Chiolak in 1909, and the couple moved to the United States either the same year, in 1914, or 1919, settling in East Chicago, Indiana. They had a son, Steve Chiolak, in 1911, but their marriage did not last. By the end of the decade, Cumpănaș was working as a prostitute; she later became a madam. Her first brothel was in East Chicago, and in 1923, she opened a second one in Gary.

Cumpănaș married attorney Alexandru Suciu, and the couple used Sage as their surname (this was an anglicization of Suciu, reputedly preferred by Immigration and Naturalization Service officials). In 1923 or 1924, Cumpănaș-Sage traveled to Romania and visited her mother, returning on board the RMS Majestic. Friction between her husband and her son led to the breakup of the marriage, and Cumpănaș left Alexandru in 1932. A year later, she opened a brothel on Halsted Street in Chicago. By 1934, Cumpănaș was facing deportation to Romania, after the authorities deemed her to be an "alien of low moral character".

On July 4, 1934, John Dillinger began frequenting Cumpănaș and her circle of friends. Cumpănaș was reportedly close to Polly Hamilton, who was Dillinger's lover. Once Cumpănaș became aware of Dillinger's real identity, she considered turning him in as a way of obtaining permanent US residence. As Dillinger was rumored to have killed two East Chicago Police Department officers on May 24 of that year, a large reward had also been offered for his capture. On July 22, after contacting the Federal Bureau of Investigation through the Chicago Police, Cumpănaș fingered Dillinger to the FBI agent Melvin Purvis, resulting in Dillinger's shooting outside the Biograph Theater in Chicago. Despite the nickname and her alleged promise to wear red as a distinctive mark, Cumpănaș is said to have actually worn orange that night.

The FBI moved Cumpănaș first to Detroit and then to California. She received a US$5,000 reward, only half of what she had been allegedly promised. In 1935, she informed reporters of the deal to keep her in the country, but deportation proceedings had already begun. Allegedly, the FBI told her they could not stop the procedures, due to bureaucracy or poor communication between branches of the federal government. She appealed the decision to deport her, and her case was heard in Chicago on October 16, 1935. In January 1936, the court agreed with the lower court, and Cumpănaș was deported to Timișoara, Romania, the same year. Making a point of shunning further publicity, she lived there until her death from liver disease in 1947.