Sam Sherwood of RNZ The mother of a five-month-old baby on life support after suffering serious unexplained injuries including a brain bleed says she's "angry, confused" and desperate for answers. She says the baby, whom RNZ has chosen not to name, was in her mother's care while she was out of town as part of an Oranga Tamariki safety plan. "I feel like the system's let me down. There was a safety plan put in place. I followed through the safety plan, and the safety plan failed me." A police investigation is under way after the baby was taken to Christchurch Hospital on Monday with serious unexplained injuries. Police say they're investigating to establish how the baby came to be injured, including speaking with family members. RNZ understands Oranga Tamariki (the Ministry for Children) has been involved with the baby's family.…