I don't know the facts of the death, but you'd better believe that there was an investigation. Any death of a child by its very nature is more than likely investigated. This was 14 years ago, but I doubt the Drs. would have called this SIDS without investigating first. In the present, you can count on an autopsy, unless the parents have a religious objection.
How do I know this? Because I lost my first DS to SIDS, when he was just 5.5 weeks old.
Like other posters have said, we don't know if the CIO in this article was connected to the death of this woman's child.
Like other posters have said, babies of co-sleepers have also died from SIDS. It happened to me: it was naptime and I nursed DS. He fell asleep and I was putting him down to go pee. I noticed something very wrong, he was turning grey quickly; he was still warm. My DH and I called 911 - he was taken to the hospital. After a thorough autopsy, 4 months later, it was concluded that it was a SIDS death. No medical reason was found for his death. My DS was not crying, not hurt by me, or anything we could find, and yet he is no longer with us.
I have also read of babies dying SIDS deaths in their carseats while in the car, or in strollers while riding through the airport. The article we are talking about is sort of unusual. Many SIDS deaths occur in cribs, that much is "normal", but it is not usually preceeded by a lot of crying. SIDS deaths are typically discovered when their parent or caregiver goes to wake or check on them; most babies seem to have died in their sleep.
Also, my SIDS support group leader says that she met a woman whose baby died during a nursing session. She says that the woman was holding the baby, and her DH noticed the baby turning grey. It was also ruled a SIDS death.
What is SIDS? We don't know. We simply do not know. It is like the term UFO, it is a diagnosis of exclusion; in other words, the babies death was NOT caused by dehydration, strangulation, blood disorder, malnutrition, pneumonia, fill in the blank ________. SIDS is when the Drs. say they just don't know what caused the baby's death, period, end of story.
As for cosleeping reducing the risk of SIDS, you will find studies slanted both ways, but the evidence and parents wisdom suggests that it is safer to sleep with your baby. My SIDS support group leader feels that sleeping with baby in the same room (in a crib, if you prefer) may also reduce the risk. Dr. Sears has written on this, too. Other ways to reduce the risk? Have a full-term baby, have $$ in the bank (some studies say that there is a socio-economic factor, with the poor having a greater risk of SIDS), nurse your baby, put your baby on its back to sleep. Remember however, that we don't know what causes SIDS.