stephen munden , 54 , described as having a ` fanatical obsession ' with small girls after he targeted a toddler on a bus .
he is described as about 5ft 8ins tall , of a heavy build , and has dark hair .
officers said they believed that munden , who suffers from learning difficulties , may have shaved off his beard before leaving a hospital , near hook , hampshire .
now have launched a manhunt to find munden - who was detained under the mental health act after sexually touching the three-year-old girl .