May 20 (UPI) -- Authorities in Britain have arrested a third suspect in connection with a fire set at a home owned by Prime Minister Keir Starmer. The unidentified 34-year-old was arrested Monday morning in Chelsea on suspicion of conspiracy to commit arson with intent to endanger life, Metropolitan Police said in a statement . The arrest comes after a 26-year-old was arrested Saturday and a 21-year-old was arrested May 13. The 21-year-old suspect has since been identified as Ukrainian national