Singer Sinead O'Connor attends the Giorgio Armani & Cinema Society screening of "Albert Nobbs" at the Museum of Modern Art on December 13, 2011 in New York City.

Singer Sinead O’Connor attends the Giorgio Armani & Cinema Society screening of “Albert Nobbs” at the Museum of Modern Art on December 13, 2011 in New York City.

*Chicago-area police say singer Sinead O’Connor was reported missing after she went for a bicycle ride Sunday morning in a northern suburb and did not return, reports The AP.

The controversial singer, currently the target of a lawsuit by Arsenio Hall, appears to have left Wilmette around 6 a.m. for the bike ride, and police received a call from someone expressing concern after she didn’t return, police Sgt. Michael Robinson said in a statement. Wilmette is an upper-class suburb about 15 miles north of Chicago along the shores of Lake Michigan.

Police said no other information was immediately available about O’Connor, whose biggest hit was a 1990 cover of Prince’s ballad, “Nothing Compares 2 U.” The gifted but troubled singer-songwriter is known as much for her fierce and expressive voice as her shaved head and blunt criticism of the Catholic Church and other institutions.

O’Connor was sued this month by comedian Arsenio over a Facebook post that stated investigators looking into the supplier of drugs used by Prince should question Hall. She also accused him of drugging her. The lawsuit seeks $5 million.

In November, she posted a message on Facebook saying she had taken an overdose at a hotel somewhere in Ireland. Irish police later said she had been found safe. The next month, O’Connor posted on Facebook that she had been detained in a hospital for mental health evaluation.

O’Connor, who was diagnosed with bipolar disorder more than a decade ago, has spoken of her mental health problems. She told Oprah Winfrey in 2007 that before her diagnosis she had struggled with thoughts of suicide and overwhelming fear. She said at the time that medication had helped her find more balance, but “it’s a work in progress.”

In 2012, O’Connor cancelled a planned tour, saying she her doctor had told her to rest after a “very serious breakdown.”