Muriuki placed sixth at the 2010 IAAF World Cross Country Championships, which helped the Kenyan women to the world team title. She was the runner-up at the 2012 African Cross Country Championships behind teammate Joyce Chepkirui, both of whom shared the team title. A week later she took third place at the Lisbon Half Marathon, finishing behind Diana Chepkemoi. Showing her versatility, she went back down to the 1500 m at the 2012 African Championships in Athletics and won the bronze medal for Kenya in a personal best of 4:06.50 min. She ran on the American road circuit in August and won both the Beach to Beacon 10K and the Falmouth Road Race. She was runner-up at that year's Portugal Half Marathon (also held in Lisbon).