Elucidating the estimated number of undetected murders by suffocation is difficult. Leaving aside criminalistical reasons it is worth to reflect about this problem from the viewpoint of forensic pathologists. 6 unknown cases of homicides from the last 15 years which occurred in Hamburg, Germany, are analysed. In five cases forensic pathologists were involved by postmortem examination, four times an autopsy was performed. In spite of questionable findings none of these fatalities could be elucidated by the investigations until the offenders addressed to the police in order to make unexpected confessions. Homicides had been performed by strangulation, suffocation or drowning. Another case demonstrates the problematic nature of false confessions.