In September, a 70 year old man apparently burst into flames in London. It's a sad event, and a horrible way to die. The press have started calling it a case of Spontaneous Human Combustion - the idea that people sometimes just randomly burn.
Of course, skeptics have spent time looking into the details of past cases of SHC, and there nearly always seems to be a rational explanation for people burning. Usually they are alone, and either elderly, of ill health or intoxicated. They're quite often smokers, or live in a house with an open fire.
A frequent explanation is that fumes or similar can make people unconscious, and from there a dropped cigarette or a limb falling in a fire can ignite. With the person unconscious, the body can burn slowly - which presumably results in a fairly quick death. The body can act as a candle, especially with flammable clothing, and burn slowly - which explains why often there is very little damage to furniture.
In this case, there are results of an investigation yet, so it's premature to start searching for supernatural explanations for the incident. It may have been an unfortunate accident, or a deliberate act.