CHICAGO (Reuters) - Irish-born singer Sinead O’Connor turned up safe at an undisclosed location on Monday, hours after police in Illinois said she was missing, citing a concerned caller who told authorities she had failed to return from a bicycle ride.

The brief scare surrounding the well-being of the firebrand performer unfolded after a series of Facebook posts in recent days in which she agonized over her 12-year-old son, whom she said had been left in the custody of child welfare authorities in Ireland.

O’Connor, 49, who has acknowledged a history of bipolar disorder, made headlines six months ago when she said in a Facebook post that she had deliberately taken a drug overdose.

She was reported by local media on Monday to have been staying with friends in the Chicago suburb of Wilmette following a Chicago performance two months ago at a tribute concert for the late British pop star David Bowie.

Wilmette Police reported O’Connor missing on Monday morning amid a flurry of queries from social media followers on her behalf. She was said to have been last seen early Sunday on a bike ride, according to police.

Later on Monday police said O’Connor was found safe but declined to give further details.

O’Connor, long known as much for her shaved head and outspoken views on religion, sex, feminism and war as for her music, shot to fame in the 1990s with her chart-topping album “I Do Not Want What I Haven’t Got” and the hit single, “Nothing Compares 2 U,” written by Prince.

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In the aftermath of Prince’s death on April 21, O’Connor accused comedian Arsenio Hall of having supplied Prince with drugs, an allegation that prompted a $5 million defamation suit against her earlier this month.

O’Connor gained perhaps her greatest measure of notoriety in 1992 by ripping up a photo of Pope John Paul II during a television appearance on “Saturday Night Live.”

In several Facebook posts since Friday, she lamented a failed attempt to win the release of her second-youngest child, Shane, from Irish authorities in whose custody he was placed by his father and her eldest son after she sent the boy to stay with them due to an unspecified medical issue.

Despite the distraught tone of those posts, O’Connor seemed fine when she played the Bowie tribute at Chicago’s Metro concert hall in March, said Joe Shanahan, owner of the venue. He said her performance “brought the house down.”