STOCKHOLM — She was off duty and wearing a bikini but that didn’t stop Swedish police officer Mikaela Kellner from catching a suspected thief. A photo of Kellner pinning the suspect to the ground was trending on social media in Sweden this week. “My first intervention while wearing a bikini during my 11 years as a police officer,” she wrote on Instagram. Kellner and three friends were sunbathing Wednesday in a Stockholm park, a homeless man selling newspapers approached, she told Swedish newspaper Aftonbladet. After he left, one friend noticed her phone was missing.