Why am I am getting Unexpected token \

Why am I am getting Unexpected token \

k ="[{\"id\": 1, \"latitude\": \"52.511467\", \"longitude\":
\"13.447179\", \"bearing\": \"0.000000\", \"speed\": \"0.000000\",
\"device_status\": 0, \"timestamp\": \"2013-08-18 00:00:00\"}, {\"id\": 3,
\"latitude\": \"53.511467\", \"longitude\": \"14.447179\", \"bearing\":
\"1.000000\", \"speed\": \"1.000000\", \"device_status\": 2,
\"timestamp\": \"2013-08-18 00:00:00\"}, {\"id\": 4, \"latitude\":
\"54.511467\", \"longitude\": \"15.447179\", \"bearing\": \"1.000000\",
\"speed\": \"1.000000\", \"device_status\": 2, \"timestamp\": \"2013-08-18
00:00:00\"}, {\"id\": 5, \"latitude\": \"33.511467\", \"longitude\":
\"72.447179\", \"bearing\": \"1.000000\", \"speed\": \"1.000000\",
\"device_status\": 1, \"timestamp\": \"2013-08-18 00:00:00\"}]"
R = JSON.parse(k)
SyntaxError: Unexpected token \
whereas
m =JSON.parse("[{\"id\": 2, \"da\": \"1\"}]")
is working without error